Thats a border bounce for a visa exemption. So not an actual visa. Visa run refers to going to another country to apply for an actual visa via said country’s Thai embassy or consulate
Depends on your needs. I use AIS “Net Marathon”, paid 800b for 6 months of 100gb/m. Not full speed but YouTube, Netflix, Spotify etc all works ok. Then can be refilled as needed with the app.
regular as in single entry? Or multiple. Try find someone with experience from KL, maybe the agoda booking is fine. Was for me with METV, but European embassy