Yup, TR is 60 days, visa exempt currently 45. It says you can only extend once but at the moment while the borders are closed they're letting people extend indefinitely
This is not true. Thailand do not have this rule - you can apply for a visa at any Thai Embassy or consulate - it doesn't have to be in your country of residence.
I applied for the TR visa because I was worried about the airline telling me my return flight was too late. But for an extra 15 days vs visa exempt it does seem like a lot of money and hassle for not much benefit.
Yes. Pre-approval means they have approved the first part of the submission, now you have to upload your travel documents and wait for the full approval. People on here saying 'no' are talking nonsense, don't listen to them!
Start with a 2 month tourist visa and take it from there. Currently you can extend a tourist visa indefinitely while the pandemic keeps the borders closed.