Your yearly renewal will be turned down. Especially if you had been waiting for 6 hours at Chang Wattana and was told to come back on the next day with a tm.30. No cap!
To Thais, UK and US embassy are their worst nightmare. UK embassy will provide a personal essay to you explaining the denial reasons very clearly in case of disapproval
If you live in Bangkok, make an appointment online early morning tomorrow, the next availability is another 30 day from tomorrow. Without appointment, you would be there from dawn til dusk!
FYI, at some immigration offices (BKK is one of), when you go for a yearly extension, a copy of tm.30 doesn't suffice. You still have to bring your rental contract, landlord ID and the house book to immigration.
Agents do for you around 500-1000. Walking in,getting there at 1pm could take you 2-3hours for your turn to be called. By the way, you must have registered the new tm.30 with BKK address before checking in your 90 day.
It's valid up to the expired date of your non-0 stamp. For example your non- 0 stamp from airport/ land border/ visa changing section at immigration is good until 15 Nov 2024 and your first retirement based on that non-o will be up to 15 Nov 2025