sounds like you've been warned. I would border bounce so fly to Bangkok, border bounce to Cambodia by a company I've used in the past and then fly back . I can pass on the company's details if required. They are tough on entering airports atm
best bet is to go with a visa company and do a border bounce. They handle everything and you don't worry. This year many people on flights back in have beened questioned at length so they are tightening up. A company I've used in the past charges ฿4000 for mainstream countries like UK USA NZ and Australia. I can pass those details to you if your in Bangkok.
why are you worried? Nothing has really changed in the tax laws. You should seek professional Dvice. Checkout Ben of integrety legals utube page as he's done many vlogs on taxation