Anonymous participant I don't think you need to do that, particularly if the company you work for has no presence in Thailand. Just apply as a remote worker with permission to work remotely from Thailand doesn't impinge on the company in the slightest
If its your parents providing the finance they should be able to provide a sponsorship letter but they may also need to show the money in their account
but that's irrelevant. The question was if someone working remotely for a foreign company created a de facto thai entity. It doesn't. The companies you refer to already have a Thai entity
If the company you work for has a presence in Thailand then that's an issue. If the company you work for has zero interaction with Thailand then there is no problem as on the DTV you are not allowed to interact with any Thai entities or any clients inside Thailand