just create an LLC... For self-employed, pls provided business license or business registration indicating the applicant’s name.... with an LLC you get all this information
there is no official amount of times on air border crossings… 3-4 is not a realistic number as I know people that use Bangkok as a hub and regularly travel every week Out/In…now with that being said eventually you will be questioned but not at a certain number of entries or it could be that you are never questioned…