Occasional P0A7A, and poor braking performance after replacement of inverter and actuator

So throughout the fall of 2020 and spring of 2021, I developed two problems in my 2005 Prius (had roughly 180,000 miles).
1. Intermittently (about once or twice a week), upon pressing the accelerator from a stop, the car would jolt harshly and red triangle, MIL, and ((!)) lights would light up. The code was just P0A7A, and no others.
2. Somewhere around this time, I also starting having brake actuator problems. The pump would run very frequently, and I started getting ABS and BRAKE lights on my dash fairly often.

Repairs I've done
So, about January, I ordered a used brake actuator from ebay, and replaced it. I had to go back in once to properly tighten the line nuts, after I had a fluid leak, but after that, no trouble for months.
About April, I ordered a used inverter/converter assembly, and replaced it. Properly filled and bled the inverter coolant. Inverter coolant pump seemed to be working perfectly this entire time; nice turbulence in the fluid.
My car was working great after that for about 3-4 months. But during the summer, it seems both of these parts may have started to fail again.

My brakes now
I don't like the way my brakes behave. I'm getting no brake lights or related DTCs, but they have very dodgy performance when creeping. If I'm stopped, then fully lift my foot off the brake and slam it back down, the car slams to a halt as it should. But if I do this more than once in a row, or if I only lift the pedal partially, so the car starts creeping along, and then I slam it down firmly, the car does not immediately stop; instead it's a very lax and slow deceleration. I don't think this is normal because I never noticed it until a few months ago, and it made me almost nudge the car in front of me at a stop light once. Is this the brake actuator failing again? It would make sense, because I replaced it with a used unit that could have been as used or even more so than the one I had originally. But I don't want to go through the extremely laborious repair if it's not actually the problem. Also, a couple months ago I replaced the master cylinder, thinking that was the problem. However, this did not change anything, so that was a waste of time. I've drained and flushed all the brake lines twice now. However, I did not have access to Techstream before, so I bled the brakes using methods described on YouTube, where it takes longer but does eventually bleed out all the air (as far as I can tell).

My inverter now
I've started getting the same exact P0A7A code every week or so upon acceleration from a stop, with red triangle, MIL, ((!)), and a quick violent jolt of the vehicle. I was getting it every couple days, but then I haven't gotten it in a week. I gained access to Techstream so I could read the sub-code, but I'm still waiting for the warning lights to trigger again. Possibly it has to do with HV state of charge and weather? I'll edit this post if I can get it to trigger again, and I'll see what the sub-code is.

Other issues
I also replaced my coolant heat storage pump just last month, for the second time. I had replaced it previously with a used unit after getting P2601. Started getting the same code again on startup sometimes, and the pump motor sounded bad, so I replaced it, with a new aftermarket one this time. But a few days ago, I turned on the car and got P2601, plus P0125 pending. I suspect these could have been related to me not fully bleeding my engine coolant system, so I did my best to redo that just now. Hopefully that won't be a problem anymore.

So, I'm mainly concerned about the brakes. Is it possible I need to re-bleed them using Techstream? If that's worth doing, I'll do it, but not if it's a waste of time. They were working great for a few months. Would air in the system cause the strange behavior I'm experiencing? Does it seem like I definitely have a failing actuator and need to replace it again?

With the inverter, do I really have another failure? This seems unlikely, but possible if the unit I got was used.

Any advice would be immensely appreciated.

 

I inspected the pads and rotors, and they look great. Pads have tons of meat left and are evenly worn.

I have not Techstream-bled the brake system. So that's probably my next course of action.

There was nothing on the HV ECU, unfortunately. So yeah, I'll probably just wait.

 

I did the whole Techstream bleed procedure today. Brakes are unchanged, and I think I actually can hear a hint of that characteristic little barking sound when pressing the brake pedal... Seems like my actuator is bad. If I replace it, I think I'll fork out the dough for the new one from Toyota, which is supposedly upgraded from the original, so this problem should not happen again.

 

Finally got the P0A7A while driving on Christmas Eve. Hooked up Techstream and it's sub-code 325. Seems like there are some wiring tests to do...