We use tot. There was nothing available in our area, but my sister in law found out if she got a handful of people in the area willing to get internet they would come and install the modem and wires. Then get each person to have their services connected.
We are super rural and have great speed 3-400mbps 5G service.
Pretty sure if you stamp out and back in you need to do tm 30. If you travel within thailand and return to the same address, a tm 30 is not needed upon return, if you have done the tm30 at that address previously.
This is what was told to me by an IO.... but tit, I'd just call and ask to be on the safe side.