You will need to deposit 800k in your Thai bank account and apply for your non-o visa. Then, for your 2nd extension you can show 12 consecutive 65k deposits into that account. After your 2nd extension is approved, you can spend your 800k. Not sure why you're frustrated, it's just the rules of how it works.
but it is valid for 48-72hrs. I.e. the reservation can be used to secure an actual ticket. Long enough to satisfy airline requirements for onward travel.
if you have difficulty filling out the form, you can ask questions here. There's only about 5 questions and 4 documents you'll need to supply... Not very difficult. Maybe difficult for a YouTuber though.
don't listen to agents! Go to the evisa website and apply for a non-o visa before you come. The process is easy, but a bit tedious. But very doable without paying someone to hold your hand.