even upon your flight landing on arrival at the airport in Thailand, anyone can submit their TDAC before going into the queue for Thai Immigration Arrivals
Or, if you would like to be more prepared than that, 3 days before your arrival in Thailand
Well, for a duly issued Thai Visa Sticker/Thai E–Visa PDF by a Thai Embassy or Thai Consulate that is still valid, try contacting the Thai Embassy/Consulate that issued the Visa Sticker/E–Visa PDF
Personally, i would give the benefit of the doubt to the Anonymous OP and say the urgent business meeting is not in Thailand nor Laos, but somewhere else
As for it being in-person meeting versus virtual meeting via Zoom, Webex, or other platform; well, being a digital nomad, remote worker, freelance drifter, etc. sometimes having a face-to-face meeting is beneficial
1.) A Thai Citizen needs to currently be in a Blue Thai Household Book ( ทะเบียนบ้าน ท.ร. 14 / Tabien Baan) in order to obtain a Thai ID Card or renew a Thai ID Card
2.) Except in the rare instance of their very first Thai Passport issued by a Thai Embassy/Thai Consulate (e.g. born outside of Thailand), all Thai Citizens need a current (unexpired) Thai ID Card in order to obtain or renew a Thai Passport
3.) A Thai Citizen can only be listed in one (1) Blue Tabien Baan (ท.ร. 14) at any one time/instance. A Thai Citizen may own multiple properties (be listed on multiple land title deeds, โฉนด / "Chanote" ), but can only be listed on one Blue Tabien Baan at a time
4.) For you to be listed in a Yellow Tabien Baan ( ท.ร. 13 ), then that can only be done at the District Office ( ที่ว่าการ อำเภอ in the Provinces / สำนักงาน เขต in Bangkok Metropolis), and also be issued the Pink Foreigner ID Card subsequently after being listed in a Yellow Tabien Baan ( ท.ร. 13 )
5.) However, a Yellow Tabien Baan ( ท.ร. 13 ) has Nothing to do with Thai Immigration matters as it pertains to a potential Change of Thai Visa Type in-country, getting an Extension of Stay, submitting a 90-Days Report, or even for a Hotel, landlord, or property owner to file a TM.30 at your local Thai Immigration Office
6.) So, what exactly do you want to do?? Do you want to stay continuously in Thailand for a longer period of time (more than 90 days, 1 year continuously, etc.)?
Well, did you directly contact and speak with someone at the LTR Visa (BOI) Office about your particular circumstances?
Or, perhaps in addition to speaking directly with someone, also write a letter explaining you would like to elect for the "Savings Deposit" option for Insurance Requirements???
Seems to be no issues, but if you are able to transfer your 800k Baht now and let it sit in your Thai bank account ("seasoning" of funds), then on your return to Thailand months later, you would not have to worry about the minimum seasoning time period of your funds in a Thai bank account, as it has been sitting there while you were away in your home country: if you were to apply for a change to Non–O in-country or Extension with your local Thai Immigration Office