Why did you get In the regular que and not just use a immigration office with a drive thru or 90 day report window? Took me all of 3 minutes to do it myself.
Technically you should update your tm30 everytime you re-enter. If it's just the 90 day report and your old tm 30 address is still the same and covers the current dates(as in you had a 1 or 2 year lease and they put the tm30 term for the entire time) you can use it for your 90 day report, but if you need a residency document or something more official the tm30 will need to match your current visa stamp.
most of them are either bitter old men upset at the requirements of the non o retirement visa or its people who couldn't qualify for it and are suffering border runs and now cant stay long time. The DTV visa is working as intended and bringing money to thailand. Lots of people can't help but want others to suffer or struggle. They also sit in thailand as a foreigner and complain about other foreigners in thailand or their home country. It's a sad bunch of entitled angry individuals.
that's correct depending on your country and tax treaty for instance student from usa are tax exempt on a student visa, but its not specifically because the visa . Its based on the individual tax treaties. After 180 days you become a tax resident, but your individual country tax treaties might exempt you.
If you don't have proof of payment received for recent work/contracts you're probably better off just going through soft power. The restrictions on the visa are the same and you could still do remote work later when your business is active again.
The 90 day report isn't specific to the DTV its for all visas that you will be in the country more then 90 days on a single entry stamp, like a retirement visa. It's standard compliance hence why it wasn't listed solely under the DTV.