Can I enter Thailand on a 30-day visa and then switch to a retirement or marriage visa while meeting COVID insurance requirements?

I'm waiting to start preparing to return to Thailand any time after nov1 when the new rules kick in . As I assume covid ins will still be in place. I intend to enter on the 30 days on entry, I had a retirement visa before or I qualify for marriage visa and intend to get one of these two when inside thailand.i had 2 vaccine jabs . The help I need is can I enter on the 30 days and change to marriage or retirement.on the covid ins I see arawan namak recommended for insurance can anyone give me a contact e.mail Oris there any other recommendations with e Mail address. I'm a UK citizen 65 year old. My old retirement visa ran out.