It works with some but not all 2 factor when I use it.
I also keep a number active on t-mobile that I used in the US and outside. T-Mobile on many plays has free roaming but the calls (if not on wifi) are pricey and the data is slow and not meant for long term use. As long as you turn off data roaming they let you use it for years and years outside the US from what others have said.
Also you should not need new phones. Just make sure your current phones are unlocked.
Not sure how consumer cellular works but if you are keeping numbers active make sure you know how roaming will work to make sure you get any texts or calls you need.
As a true tourist only planning a year or less with no history of staying in Thailand you likely can pull it off with visa free entries and extensions if your nationality qualifies.
60 days + 30 extension
Do that 2-4 times.
If you are pulled aside (not likely till the 3rd or 4th time) just explain and show you are not illegally working and do not plan to stay long term.
Worst case you go to a neighboring country if they won’t let you in or warn you about next time.
But honestly for real tourists I think you will be fine as long as you don’t push a year.
Side note if you want less hassle consider the Philippines. Depending on nationality you can extend up to 36 months without leaving the country and just a flight in and out resets it.
You could also just travel around regional. Do 90 days to start and 90 days to end in Thailand. Just add a few months in the middle visiting one or more other countries.
You can do it until the officer you get decides you are breaking the “rules”.
Normally when they think you are living in Thailand, especially if they suspect illegal work.
That could be as soon as the 2nd (possibly even first) and could be years and years in a row. That would be rare without “help” for border runs but technically possible.
The officer you speak to along with their supervisors can do whatever they think is right. Most will be warned not outright denied entry first.
TLDR: you realistically can’t live on visa except entries unless you have “help” with border runs.
If you plan to stay beyond 6 months a year it makes sense to look better visa options. The new DTV is perfect for many who want this but lack the funds or desire to pay for the elite/prestige.