Do I need to provide permanent accommodation for my Thai visa application or is a short-term booking sufficient?

For the actual visa you need to read the requirements listed on the embassy/consulate website who you are applying from. Email them if you are unsure as some may be flexible. Some embassies requirements are not always the same and differences between visa types. The multi entry tourist visa for instance at my country embassy required accomodation for the entire period until my first plane flight out. If want to move around you can always make changeable bookings. Single entry tourist visa I have been told they only needed first night. So best to read the embassy’s requirements

tm30 is more for residents

I had the tourist extension and all they needed was the address

You need a TM30

Some regions ask for tm30, some don’t? It will depend on where you go.

For 30 days extension on a 60 days tourist visa (or 30 days visa exemption) in Thailand you use accommodation at date and a updated TM.30 when you do the extension and can move around as you wish. Hotels update your TM.30 at check in.

When you’re applying for a tourist visa is as mentioned above embassy depended. Most accept booking for the first days.

You need to check the website of the embassy you're applying through and see what they say. Most only want the first place you're staying so a booking of a few days should be fine. But it all depends on the embassy requirements.