. If they see the sticker in the passport they almost certainly use that. But you can ask the imm. officer. Should you have an E-visa (printed .pdf) your chances are a bit better, but still not sure they do that. Think they can see in their system you have a tourist visa. Not sure about that.
, I am not a native English speaker but you say 'application'. You not do any 'application' with border hops/bounces. You come in on visa exempt, multi entry tourist- or non O multi entry visa. The only difference in my knowledge is that you can do this by land borders only two times a year with visa exempt. And another difference is only the imm. officers themselves. Does not matter by land or 'by airport imm' coming in. They can be giving you a hard time or not.
: If you want a Taxi instead of bus or train, I always use 'the trick' after coming in the arrival zone, to go upstais again to the departure zone, go out and go through one of those touniquets against the direction of rotation. There are the Taxi's who bring people. Constantly the airport police is summon them to go. They rather take you then leaving empty so your negotion position is quite strong 😉 Going price is from 2,500-3,000฿ to Korat.
says e.g. a 60 day extension visiting Thai family (Think the visa (rest of the time)) is void then ? But also you can make a year extension if you have all requirements before all border hops are used. Possible that this only could be done in covid times ? Just ask your imm. office. Think that's the safest approach. Normally you have to do the border hops indeed. If you do the last border hop just before the visa is expired, you can almost get a year and 3 months stay.