What should I know about obtaining a SETV to Thailand from the United States in January?

You do not need a service, as there are too many steps that are specific to you that a service can not help you with. You need health insurance that covers at least US$100,000 for covid-19. You need a doctor issued fit to fly certificate. You need a covid-19 test done no later than 72 hours before you fly. You need the quarantine hotel booked, and paid for, and the hotel you are staying at after quarantine booked and paid for. You need to personally mail your passport to the Thai Consulate for your visa. You need to personally book your plane flight. And you need to personally get your certificate of entry from the Consulate. A service can tell you what to do, but they can not do most of these things for you. The Thai Consulate will help you just as much, and they are free. A service now is a waste of money. On a side note, after looking at your profile, a few comedy venues in Bangkok have opened back up, and are booking entertainers, and have open mics.

How will you be booking your flight? Just curious if I should book my flight from Lax before filling out all procedures on embassy site?

General consensus is that these agents aren't worth it and that generally they just advise you on what you need which you can easily find yourself on the embassy website or this group.

SETV is easy to get, just make sure you are aware the process is different from the US than other countries.

This webpage has everything you need /05/trsingle_entry/

SETV isn't available to high covid risk countries.