2013 Tahoe LS 5.3 Vin 0(250k miles) Low oil pressure

I got a 13 Tahoe that I’m feeling like giving up on. On start up I got about 20 normal psi, then it just slowly proceeds to drop to roughly around 5-8 psi, then just stays the starts to flash “Low oil pressure.” I thought cause it was originally to replace the pressure sensor to no avail. Following that I paid a mechanic to diagnose the issue, and he said that the pump was going out, only throwing about 10psi, and needed to be swapped so roughly a grand later I still have low oil pressure and a check engine for low oil pressure. The mechanic informed me that before touching anything I got a rear main seal leak, which is now much more visible because of a new pump being put on. But while driving it comes up to about 30-35, which was better than before but still not great. I’m not keeping the thing for much longer, hopefully, but still want to be safe on the road. Any ideas??? Also, I put an oil thickener to see if that at least slows the leak and helps build pressure. But right, I don’t want to feel like I was a bit in the ass and just used 1k to not even fix the issue.