Alarm System Randomly Engages - 12V Battery Drain - Reboot of LCD Display

Where to start? Have spent the afternoon here on a few things and garnered some insight.
Prius Three (I think) - 2018
We have an extended 5 year 100,000 Toyota Care Warranty. Car has 90,000 miles and 5 yrs. up in October.
Car has had intermittent problems for which it has been brought to the dealer for repair their fixes have been software update for Reboot of LCD Display and replacing the 12v batterrm for the alarm system problem. After replacing the 12v battery less than 18 months ago - because they told us that low battery was the cause of the problem... we had a no-start a month ago (no lights on, nothing to cause it) and jump by AAA, we took it in again to be looked at. Dealer: Battery is fine, no problem.
This week: Car started the random engagement of the security system alarm and blasting horn which has been a recurring problem on and off itermittently for 3 years. Of note: It doesn't do it in winter, mostly when the weather heats up 90 degrees and up (we live in Texas). Don't know if that could have anything to do with it (or the other problem with the LCD Display I'll get to later, probably not. Anyway, car alarm spiked twice while we were at small restaurant and I recorded exact time and date. Took it to dealer Monday. Approved the 3 hours, $600. diagmostic fee (which will be reimbursed if faulty part is culprit and covered under our maintenance agreement). They have had the car for three days. They we able to replicate the problem in the shop and have replaced the battery we installed less than 18 months ago after it did not pass the load test. However, there is apparently some minor draw on the battery causing this problem to reoccur. Their master tech is stumped and can't find where the problem is coming from. So, asking for any help the sage folks here may have for this issue.
Next...we have had intermittent problems with the LCD Monitor "rebooting." After rerading numerous posts on here, it appears to be a problem with the larger screens which our 2018 has (as well as the Prius Prime models). This started in 2020 and happened multiple times. Took it into dealer under our warranty and they couldn't replicate it. When it happened on the freeway driving back from a trip, i noted date and time and took it in to dealer. Their solution was to completlely reload the system software, which seems to help for a while with the problem, but now it is again doing the rebooting (recirculating the screen).
So......I am just wondering if the Alarm System malfunction and the Rebooting of the LCD Screen can possibly be connected to the over time battery drain? Can a fuse, switch or component be causing these?
Of note: The USB outlet in the car has been faulty and on and off again working. Might this be shorting out and causing a battery drain? This also was reported to dealer - they could not replicate it and tech said only to use an Apple cable in the USB outlet. That didn't work consistently, so I opted for using the 12V outlet with car adapter. Could having this plugged in cause the LCD Monitor Reboot?
I'm really stabbing in the dark here, thinking that somehow all these things are related. I appreciate any comments to help me....

 

Well, we already told them we are not paying the diagnostic fee if they don't find what is wrong. If they find a failed part or malfunction (not caused by the usual exclusions of things like mice (vermin), water damage, etc.) then our Extended Warranty covers payment of the diagnostic fees and repairs. So we will see. But hoping someone here has some suggestions or has heard of a similar situation. After reading the NUMEROUS posts about that larger monitor having issues with iphones, cables, bluetooth and Enturne, I'm not so worried about the rebooting of the monitor display, though it is a nuisance and something Toyota certainly KNOWS is a problems and hasn't fixed. But this alarm system and battery connection is just not good. I suppose if this dealer doesn't find it, my next recourse is contacting Toyota directly. But again, hoping someone here has suggestions/help..

 

Yes. With either the key fob or the interior lock on the armrest. I usually push the park button, then hit the power off button. Most times, I lock the car using the interior lock button on driver armrest. The car sits there - locked and parked in the driveway, on the street, in a parking lot, under a tree, uncovered in the sun. It doesn't matter. The alarm randomly goes off in any of these situations. This can happen within a few minutes of turning it off, or totally randomly hours after turning it off. And it doesn't happen every time. Completely random, but it's a real "B" when it goes off in the middle of the night, or early in the morning, which it has in the past done. I surmise there is a bad switch/sendor whatever that selectively kicks the alarm off. And is possibly draining the battery and causing the alarm to go off. So far all the Toyota service advisor and mechanic have said is that the 18 month battery was bad (again) and that the problem is continuing to be replicated this time even AFTER replacing with the new the battery. It got better after the battery was replaced, but then after 18 months, started up again.

It's pretty bad when a 72 year old woman out of desperation is reading years and years of posts trying to troubleshoot this when the dealer is perplexed. Lol, seriously.....

From reading other posts, which I have been doing for hours, possibilities seem endless. Could it be:
A faulty door actuator sensor? This kinda makes sense to me...could it be a certain way the door latches/closes/locks that could cause this sometimes and not others, or a short?
Faulty dome light switch or power?
Battery cable relay switch (is there one of these)?
Stuck Panic Button Key on FOB (though I have examined both FOBs and see no evidence of that)
Faulty switch on engine hood sensor?
Main Body ECU failure/connection?

Frustrating.....

 

I'm passing this along to them. One would assume they have done this, however, with it "requiring a bit of work" maybe not.

 

Yes, factory installed Toyota alarm. So, they did quite a bit of examination and trouble shooting. Finally decided that the transmitter on one of the key fobs was bad. They replaced it with a new one, and reprogrammed our second one to match. Additionally, they updated the software in the car. We will see if this holds the problem at bay. The recirculating the display monitor was doing seems to be a common problem and connected to iphone. I'm going to touble shoot this on my own if it happens after the "software upgrade" they applied. So for now, we are good. We decided to get a new 2023 Prius XLE and trade this one in. We have two payments left and the Extended Warranty (5 years or 100,000 miles) will expire. Rather than purchase another extended warranty on this 5 year old car - and take the chance something will go wrong that is NOT covered, we are just going to go the new vehicle route. At 72 years old, it will most likely be our last new car, we are just going to enjoy it. So now, actively looking for a new Prius and have given the dealer a deposit to hold one as they come in that is most like our wants. Tough market now and short supply. Our dealer doesn't upcharge though, so that I guess is a plus.