I was an expat that was living on 600$ for most months of the year in Thong Lor, Bangkok even with most expenses included. Minus furniture because it comes with the place.
It depends on lifestyle. I know people who only earn 600-800$ a month, and they have a similar standard of living minus some luxuries and conveniences.
I can't wrap my head around privileged-passport holders (eg. Norway) not planning their bookings and travel/exit dates to avoid overstays.
I know it could happen sometimes, but it should be a rare because the small issue is preventable by just counting dates on the calendar before buying tickets. How else can one express that overstaying a tourist visa in any country is something you don't want as a record on your passport. Especially, you don't want any record of overstay in a country like Thailand, because most visitors will want to visit again before this passport expire.
So, the proper solution is to go to immigration and get an extension stamp. But well, you can take that record of overstay too at the airport. That's up to one's personal choice based on how much privilege one has.
The way the Thai visa system is setup, you’ll find yourself much much happier with the dependent visa. Also, immigration don’t care much whether you’re a full time dependent or not.
Unless you need to prove your tax receipts or income statements from a government entity in the near future, I’d suggest stick to the dependent visa and do whatever you want to do. If you find potential issues with your job, income, legality after a year, consider changing your visa.
You'd qualify for one of the SMART visa categories if you're going to work with Thais and under a Thai company. That's easier in case you don't qualify for LTR