A friend of mine imported a Huawei phone, came to Thailand through alibaba. Was told it was illegal, then was told had to pay duty 1000 odd baht, import permit 1000 odd baht, and fed ex did the clearance 1000 odd baht.
If I'm not wrong, you're allowed 2 border bounces by road, the rest has to be arrival by aeroplane, back into Thailand. This is unless you have a tourist visa, 2 months, from a Thai embassy.
No insurance company issues covid travel insurance in the world. Thailand will have to pass the pandemic insurance that they suggested, a while back. That gets one point sorted. Covid certificate is not hard to get. The third is quarantine??? Quarantine visitors for 2 weeks at ones expense??