The borders might be closed until mid 2026 or even permanently.
You can travel to Cambodia by land if you so wish, via Laos. However, due to anti-Thai sentiment, I wouldn't count on a Thai vehicle being permitted to enter Cambodia from Laos, though there are cross-border buses operating between Pakse and Siem Reap as well as Pakse and Phnom Penh.
Otherwise, you can fly...although many airlines have reduced their flights between Bangkok and Cambodia since July.
Since it's an e-visa, I don't understand the need to carry 2 passports. With a traditional visa sticker, then yes, that makes sense and I've done it that way before.
You had a "wild flight"? Sounds like a turbulent flight? Just the way it is....it's rainy season and it will be bumpy. You might experience what I did a couple of years ago, while flying towards Bangkok out of Singapore on SIA - flying through a thunderstorm and dropping probably a couple of dozen feet. It is what it is. Can't be avoided. It's the reality of air travel.
If you're afraid of flying - wait until late October or later, which is when the air becomes calmer as the rainy season comes to an end, though anywhere south of Samui will experience a second monsoon.
Or just travel by land. Other than Cambodia and most of the Burmese borders, the rest of the region remains open. Laos and Malaysia are your best bets.
Don't be ridiculous. A DTV is a non-work authorized visa. It has the same "employment prohibited" restriction as tourist visas or retirement visas. In practice ALL of these visas allow you to work remotely for non-Thai based entities. Stock trading is about the same "work" as opening your banking app or internet banking anyway.
You're being absurdly ridiculous. As is if your time is that valuable. You probably spend way more than 23 minutes a day scrolling through this very forum. I find Ride with Gabi's videos quite informative.
To be honest, I don't see why any Thai embassies or consulates, all of which are now on the e visa system, make a distinction between residents and non-residents anymore given that no one is allowed to apply in person anymore (a very backwards move) thus no issues with overcrowding, which would have likely been the main reason for having this rule in the first place.
Of course, where this rule is still in place now, it could simply be to reduce the Consular staff's workload so they don't have to sort through as many applications, though in the case of China, you would never see any large number of applicants being foreigners anyway.
Everything in China is dominated by locals...unlike say in Thailand, where you have expats everywhere, in China, foreigners are rare.