Ignition and 12v Battery problem

Hi have a 2009 pries GEN 2,
Over winter has issues with poor 12v battery, had it on charge and battery maintainer regularly, as battery test did not indicate problem with battery.

the problem seems to be getting worse now, but something new I have noticed is, at times when I turn the car off, close the door and get out / lock it... it occasionally used to start beeping. and I could tell if this started beeping it meant next time I come to start the car I will definitely have problems.

another new discovery is, on occasions I turn car off and close door, and lock car suddenly the car turns on to ignition maybe after a few seconds or minutes (its just ignition not "ready")

and now I am very frequently having issues in morning where the clock resets and also the reverse camera and its calibration (with steering) resets indicating the battery has been disconnected or died.

and at times the car is completely dead I can not start or get any light, However a solution to this is if I open the driver door and close it again this must move something and create a connection which then allows me to start car.

I have checked around for loose connections but can't seem to find anything, has any one experienced this or can any one advice what I can look for?