Check if you can just walk in or need an online appointment. They can get booked up well in advance

You'll get nothing of any size and cooling capability with 12v. Solar plus battery banks and sizable inverter. 100k

Chest freezer 5k

Note that you need to submit your application for change of visa to non-o with 15+ days remaining on your stamp (for most immigrantion offices)

Plus 800k in a Thai bank

Fine for not reporting you weren't at your residence. That's a new one on me...

Anyone else have this problem?

If you find your airline requires a return flight within 60 days, you can buy a fully refundable ticket to a nearby country and cancel it after arrival into Thailand

You report every 90 days, after arrival into the country. It resets when you leave. Your landlord/partner should submit a TM30 on arrival. Both often easily done online

Lens

Assuming it's not CM...

Depending on your living arrangements, your partner or landlord will need to submit a TM30 for you. Easy to register and do online. Then you will need to go down to immigration and complete a change of address form. Changing the address listed against your visa to that of your TM30. Ask them for a copy of the requirements that office has for you to renew your visa with them.

Note, depending on your bank it can take a few days for you to get the annual statement.

Where is the visa stamp in your passport from? Chiang Mai?

Where do you or your agent do your 90-day reports?

The office you have to go to will be dictated by where you are staying now, tonight. Your landlord will/should have reported your stay TM30, as them for a copy (screenshot) of their receipt and take it with you to the immigration office they use.

For future reference you don't have to wait for the last day, there's no penalty (days lost) in going early.