@Deano ************
certainly if your flying in and out of the country ( Thailand ) you can come and go as many times as you please . I note your Spanish? .. so currently you will get 60 days on entry + 30 extension, that’s your 90 days as you know .. fly to Cambodia stay just a couple of days if you like
And fly back in and start again 60 days + 30 days .. you could in principle do that forever or certainly under the current rules , Flying is the key here , not by road .
You might get questioned about finances and as to why you keep coming and going ? .. ( they immigration don’t like to think your working illegally) ..