Neither of those. The date to focus on is the one that says ENTER BEFORE. That is the last day you can use the METV. After that date, you would need a new visa (or arrive visa exempt depending if your passport country is allowed to do that...USA is allowed).
, it sounds like your METV is in no kind of jeopardy if you extend 60 days more under the covid extension program. You just need to decide how much time/money/hassle you want to deal with if you would rather move onward to a neighboring country(Cambodia?) and return before your METV sticker expires.
or other mods can answer accurately. But I believe covid extension only cancels your ability to convert to other types of "in-country" visas. Covid extension just gives you more time to stay here. If you leave, and your METV is still valid...you should be able to use it to enter. That is...unless for some stupid reason they announce all METVs are no longer usable. I doubt they will do that.
This sounds correct. METV has unlimited ins/outs during its validity. The challenge right now is it is not easy to border hop. So you have uncertainty of time/money/rule-changes. If you're okay to roll dice on that...by all means travel onward. If not, why not stay put another 60 days to "wait and see" what plays out after January? You can do a lot worse than be in Thailand another 2 months. ;)
How much longer is your ME-TR valid for? It might not be worth the hassle exiting. A Covid extension only costs 1900THB and gives you 60 more days in-country.