Will I face issues re-entering Thailand on a new visa exemption after a Covid extension?

You will be asked some serious questions on re entry, such as why you live in Thailand long time without longterm visa. Get a proper long term visa before you come back.

Almost certainly you’ll have issues. To mitigate entry issues you need to provide 3 proofs for entry into Thailand.

1. 20,000 baht cash or equivalent in a major currency. It needs to be in cash. A bank statement, credit card or phone app showing you have funds won’t suffice.

2. Accommodation booked for at least the first few days. If you’re staying with family or friends then have them write an invitation letter for you to stay at their place.

3. A ticket out of Thailand booked within the number of days your entry allows, regardless that you can get an in country extension. 30 for Exempt, 60 for Tourist Visa (although the likelihood on being asked if you have a actual tourist visa is minimal). Bus train or plane. The two former must be an international ticket out, not just to a border town where you could walk across a border.

These won’t guarantee entry, but they’re the three things they can ask for.

My advice is to get a proper visa. Re-entering on exempt with a string of covid extensions they're going to know you're working illegally in the country.