Computer Lag

I'm sure there's no guarantee since this most likely involves aftermarket items but almost a year ago I installed an Apple CarPlay unit in place of the stock radio along with a 12" JBL Powered Subwoofer in the trunk. Everything functioned as normal for the first several months but a few months ago, if I leave my phone plugged in or the headlights on for an extended time, the backup camera will take sometimes a few minutes to show up after the car was put into reverse. Most commonly, I would back up to where I needed to go and then put it in drive to start driving then it would come on and stay on for the duration of the drive. More importantly, which is actually the main reason I'm asking for an estimated guess, my passenger headlight will come on for 5 minutes like normal and then start to subtly flicker and then flickers a little faster and then shuts off while the driver side is still on.

So the main question is whether the CarPlay unit and the Subwoofer are drawing too much current for the computer to handle. I've tried not doing anything with the CarPlay unit upon startup and I still get the same issues. Long car rides don't make a difference as the issues are the same as I thought would potentially help if it was a power issue since the car charges the battery when driving. I'm thinking that the 12v battery was fully charged when I installed the CarPlay unit and Subwoofer and over a few months it has drained it down to it's minimum. I haven't had any issues with the computers in the car not starting up or anything. Literally just the headlights and a laggy backup camera. Both issues coincide with one another.

Any input is appreciated.