It is easy to get a 30 day Extension of Stay based on tourism.
You can get a copy from the landlord within 24 hours after arriving, he has to make the registration on line, using the app or in person. a Copy for you looks like:
Why do you think you can not visit Thailand again?
As long as you fulfilled the entry requirements due to covid, have a valid passport and visa, not mentioned on the wanted lists of Interpol of FBI, not being blacklisted, I do not see a problem.
1. Plan sounds good, there are always risks to travel and to enter different countries.
2. There is NO maximum time you can stay inside Thailand, a stay inside Thailand is only limited by the time you get with a visa and extension of stay.
Some visa and extension of stay will give people 1 year of stay.
As long as the date on the visa, enter before or valid until, is in the future you can enter Thailand by land, air or sea and get maximum 1 year of stay OR until the valid until date of your insurance, which ever comes first.
Visit for 90 days: OR the Non Immigrant O visa based on being over 50 years of age, which gives you 90 days on entry.
OR the Single Entry Tourist Visa which gives you 60 days on entry and can be extended once with 30 days on basis of tourism.
In 2024 a long way ahead, but the retirement visa also know as the Non Immigrant O visa based on being over 50 years of age from the Thai Embassy and when arrived in Thailand apply for the 1 year retirement visa also know as an Extension of Stay based on being over 50 years of age at the local Immigration Office.
The system is not to change your address, you do that with another app or in person at the Immigration Office with the house owner/landlord within 24 hours after arrival.