I have been traveling around Thailand throughout the pandemic under the WTT scheme. Some of the hotels were fully booked and not a foreigner in sight.
Not always the case, beginning of last week we were at a resort in Khaoyai and the only guests in the hotel, asked to eat in the room. The following night at Kabinburi a bit better, maybe 20% occupancy.
All about where and when, Thai tourist areas can be busier than those frequented by your "farangs".