Normally you would go to Vientiane and get the Ed visa there and head back to Thailand on an Ed visa. Now because it is very difficult or impossible to travel to neighboring countries the easiest and closest place to go would be Sri Lanka for a visa run.
Hopefully the land borders will open soon.
Other option would be the bullshit volunteer visa, there are some places still offering. There is one major problem w this visa which is if you leave Thailand the immigration will not let you back in with this visa. So if you get the volunteer visa DO NOT travel outside Thailand. It is about the same price as the Ed visa but u don't need to go to classes