I have never needed a rental contract to get an extension. I don't rent anyway.
I've only dealt with 2 immigration offices. Nakhon Pathom, at the time Ratchaburi didn't have an immigration office, and Ratchaburi.
There have always been people masking in Thailand. Pre covid it was because of air pollution or when someone was sick they would wear one to try and not spread it. So when covid came masking up was no big deal for everyone.
At this time some mask and some don't. It's up to you.
I had the same thing happen to me but in the US. I would get severe pain at first it would last 15 minutes or so. But over the next couple of years it kept getting worse and longer in duration. The pain was so intense it would literally floor me. I would go to the doctor and at first they would just tell me it must be gas pains. Then the diagnosis went to irritable bowel syndrom. The day before I went to the emergency room because the pain wouldn't go away I had gone to see my family doctor again and they just gave me more medicine for IBS. At the emeregence room the physician looked at me and almost immediately said I think we need to remove your gall bladder but we will do an ultrasound first to be sure.
I have no idea why it only took him a few minutes to determine my actual problem but my regular doctor could never figure it out in a couple of years.