Detailed PS4 Pro issue

I hope I can get some guidance here. I really don’t want to have to buy a replacement. Ok, PS4 Pro had been peed on by one of my cats. I thought that was the issue but seems not. One day it just shut itself off. After unplugging and starting back up it took me directly to safe mode. I would try to restart in safe mode and it would act like it wanted to then beep and take me back to safe mode. Tried rebuilding database in safe and it tried. Halfway through it beeped once I believe ( I do recall hearing a few times it beeping three times but ultimately it would go back to beeping once and putting me back in safe mode) then went back to safe mode. It did stay active enough to do an update from safe mode then shut itself down again. I figured cat pee fried it or at least crystals from dried pee might have been shorting something so I ordered a few cans of electronic parts cleaner and waited for it so arrive. When it arrived I stripped the PS4 down and found no instance of pee anywhere inside but I thoroughly cleaned the system with parts cleaner and compressed air as I searched for an answer. I deduced that the power supply must have given up the ghost as that’s where most topics led me so I ordered on.
When that arrived I tore the system down almost completely, applied thermal paste and installed the new power supply. Fingers crossed.
It started booting up. My heart was racing. Rebuilt the database. Everything looked fine. It got to the accounts log in screen (YES!) and … shut down.
It is now back to never coming leaving safe mode. It tries then beeps once and goes right back.
I listened very closely and while not very loud I did hear the fan and felt hot air coming out of the back for the few seconds it tries to restart from safe mode.
My question is this. Do you think it is overheating since it got as far as it did with new power supply.
Should I replace the fan and while I’m at it, the thermal paste was a few years old. Would that make a difference. Replace the fan and apply new thermal paste?
I’m at a loss. I will go as far as needed to fix this. I don’t want to loose any of our information. We’ve had the system for like 4 or 5 years now and we use it for all our streaming services on top of gaming and BR.
Thanks in advance