Do you actually wish to study? Less institutes are now able to give out the ed visa and you'll very much be stuck in your place of education (the area, not the school) if you wish to explore the country. If you're just after a long term stay you'll probably find the odd trip to neighbouring countries will be cheaper and easier now that borders are open
It really amazes me that so many people choose to use "agents " for simple visa things. Although many Thai websites can be a bit confusing, with just a few minutes googling and a couple of questions on forums like this you can normally do everything cheaply and legitimately. I can possibly understand the need for one if you're trying to sort a business visa and they are actually qualified lawyers who specialise in it but so many people seem to think even the simplest visa issue needs the assistance of an agent and while so many of those people exist people will be happy to charge them for it. Never hand your passport to a stranger
yes, and if you don't meet the requirements you should hopefully be aware of the risks you're taking. I'm talking more about the ones who completely qualify but think it's all too complicated and use an agent unnecessarily,.of which there are many