What should I do if my host won't submit a TM30 for my short stay in Thailand?

Don't worry about it. Just get a TM30 for the place you're staying at before you do your 90 day report.

Get the TM30 from your long term stay location where you will be once you hit the 90 day mark.

I also have a DTV visa and I'm submitting a 90-day report. You can apply by getting a TM 30 document from your last stop before you go. Because I think it would be too much of a waste of time, I'm giving my passport to a hospital visa office for 650 baht so they can process it for me.

Your TM30 needs to be submitted within 24 hours of your arrival at the property. It is your landlords responsibility to do this and if they are running a short term rental business then they most likely will have an account set up with immigration and can register you online in under a minute.

Total BS regarding only being issued a TM30 if you stay 30+ days, its a legal requirement to register you within 24 hours as I said.

Now there might be some confusion with the fact that some immigration offices will not issue you a certificate of residency if your stay is under 30 days but that is different.

If you want a TM30 your choices are as follows.

Spend the time and go to immigration and register yourself, if you havnt registered within 24 hours of your arrival at the property the might fine you or the landlord.

It's up to you to tell them WHEN you arrived, they will not check.

Second option is to wait until you find your permanent rental home and do it then .

The chances of getting caught without a TM30 in 9 days are very slim but they will go after the landlord for not registered you.

Edited

You will be fine. The TM30 looked at for the 90 Day is your current live location.

Before youre due for the 90 days, check into a hotel and ask them for a tm30

Worst case is a fine of 1000-2000 baht when you report, depending on the officer/district. No strike on your record or anything. Or you can leave before 90 days and come back same day.

They will not fill it because it's illegal for them to accept customers for 9 days without hotel license. Find a real hotel that will accept to do so for you or wait for the next condo owner; your report is in 81 days, that shouldn't be an issue.