This will not help at all. It could even cause issues in the future. As long as u travel a lot and don't stay more as 50% of the time you should be fine. For every case ask your girlfriend to handwrite you some short letter in thai and print her ID + phone number. However problems occur when you stay mostly in Thailand with some tourist/edu visa...
not really, depending on your school and most probably on 5he city/immigration office. Main issue with education visas is to pass the immigration officer at the airport, thay could be suspicious, at the local immigration the schools usually have some "friends"...
I applied for 2m tourist visa in Bulgaria 3 months ago, was requested for bank statement, employer's letter, insuarance, prepaid tickets + return and rental's contract. Processing time was 3 weeks. Before covid the same visa was issued just for 5 min and the only requirement was prebooked(not paid) tickets. I would never come on holiday to Thailand if I didn't planned to stay longer and my wife wasn't here...
U can even stay 8 months with this visa, as u can get stamp for 60 days 1 day before the expiring date of the visa. Keep in mind that u will still have to do thai pass and insuarance before each entry.