it's very low. Well under 1%. For USD to send 65,000 THB Wise charge 0.68%, or $13.79. That's $165/year, or 5,300 THB. I think you need to see that as a "cost of doing business".
the bottom line is 65,000 or more has to appear on your Thai bank statement. So you need to ensure that when you send, you send enough that 65,000+ will appear AFTER any fees.
Sometimes with "free" SWIFT, the trick is they give you a bad exchange rate. Most of the way banks make money on international transfers is the exchange rate, not the fees, the fees are small comparatively. So when comparing you need to compare how much THB you get at the end for a given amount of money in.
Usually with SWIFT transfers even if "free" on your end, the Thai bank will take 0.25% min 200 max 500 receiving fee, so you would have to add this at least.
Wise will give you about the most competitive rate but will also guarantee an exact amount into your Thai account. If you say 65,000 in Wise, that is what shows up in the account, exactly. No 200-500 fee. They charge fees but these fees are best compared to the bank's exchange rate spread, and they are usually lower.
Some banks can be competitive with SWIFT transfers. It depends on the currency too, for example Thai banks give good rates for USD and some regional currencies like MYR so they can be competitive in those currencies. Usually though Wise is cheaper.
Thai data SIMs come with a local phone number, even if they can't make calls. Most of them can make calls too if you add money to them- they really are just normal SIMs with a data plan. I don't think there would be a problem using your bank app on that as long as it is registered to you. My understanding, you would still be getting a Thai data SIM for the internet connection and Xpatphone is a way to VOIP your UK number. I think that would be OK.
the rule is you have to be in the country or countries the embassy serves. They are in Indonesia. You are allowed to apply from anywhere in Indonesia, as long as you stay in the country during the application. It's a big country. Most embassies do the whole process online and don't require a physical interview. They emailed the embassy and rescheduled the interview giving time to travel to Jakarta, so obviously that is all fine. You're not being helpful here.
it lists four stamps and the first one, ผ.60, is the most common one that most countries get. It doesn't list an exempt unilateral 90 day stamp I don't think but ผ.ผ.90 which is the Brazil/Korea one. ผ.ผ.30 I think is the bilateral treaty Russia one.
It does mention special screening for certain nationalities that are involved in problems, but as far as I can see the categories of stamps listed are just all the exempt stamps, not one in particular.
Anonymous participant 457 like you say it sort of does depend where you live. I fly out at least twice a year anyway but if you were looking for either the fastest or cheapest option from Chiang Mai, that is a land border run to Laos. Even more so if you were somewhere like Chiang Rai. There is an international airport here but no longer good options for same day return (used be possible to go CNX-KUL-CNX same day).
Anonymous participant 457 there have been several reports already on this group that DTV holders are not being allowed to do land border bounces, either at all, or same day. Some agents can apparently get around this for a fee. Very possibly this restriction on visa holders in the wake of recent changes is not permanent but awaiting clarification, but that is apparently how it is now just in the last few days.