TM30 is a legal requirement for EVERY property owner to do within 24 hours of arrival at that address. If you've stayed at a hotel you have a TM30. Ask your landlord or hotel reception for a copy. You cannot do a 90 day report without having a TM30. It literally has nothing to do with your visa type.
You can apply for a 30 day extension each time you enter. Or you can apply for a tourist visa from the Thai embassy before you travel which will give you 60 days when you arrive.
But right now no one knows if or when visa exempt will switch to 30 days.
I didn't say you're "entitled" to enter. I said it doesn't matter how you enter. There's no requirement or expectation that you're entering from any location, via method, on any date. You can do whatever you want and it makes no difference in regards to your visa for entry purposes.
I don't have this experience as my company is publicly listed, but this is by far the most difficult requirement for the vast majority of people who want to apply for this visa. Many privately held companies simply will not release this information.
There is no rule that says you cannot do that, but do know that there are MANY reports of people getting pulled out of line at the airport and grilled for an hour about why they are back so soon after just spending 90 days in Thailand. After 90 days they are looking at you suspiciously as that's not the normal behavior of a tourist. You probably won't be denied entry for your 2nd entry, but they might warn you that it's your last time entering without a long-term visa.