With "Laos border control suggested me I dont have to enter Laos, can just go back", they still take the money for the visa and stamp you in and out. They just do it in one go, putting the entry and exit stamps in at the same time. It's just a slight time saving vs going in and coming back and presenting yourself a second time. From the Thai side, it looks exactly the same as whether you went in to Laos or not.
are you sure that was posted by immigration? I saw it posted in a number of groups but there wasn't confirmation as to the source, whether it was immigration, a visa run company or agent, a hotel, etc. I personally suspect it will "reset" on 1 Jan, as that is how they did it before. But I am not sure it has been 100% confirmed yet either. Also these new rules seem to be guidelines with somewhat "soft" interpretation, rather than a hard "2 per year" as before. Some people are still getting more than 2 visa exempt entries per year, if they don't look like visa runners.
the last time they had a limit of two land visa exempts per year, it was per calendar year and it reset on 1 Jan. So while there was a limit of 2 per year you could indeed do 4 in a row if they split over the new year. It's not clear if that will happen with this new rule, but that is the way they did it before, so it's at least possible.
that's Bangkok Bank, not Krungthai. I've seen other people post that Krungthai policy is no app access without long term visa but they are not closing already opened accounts.
As others have said, right now it doesn't particularly matter. Immigration at the border do not look at this. If you never need anything from immigration in country you may be able to just never do them at all. Personally, I am going to do them regardless, as it is still a legal requirement and there are other things that used not matter, but then started to matter. (Like overstays- you used be able to just pay the fine and as long as you paid this it didn't matter if you were overstayed for years. Now that matters a lot, and overstay history can matter if applying for a new visa.)
immigration will almost certainly want to see the passport with the entry stamp. Check in are unlikely to care about that. If you have both you'll be covered either way.
it could work either way. Elite used work this way, and you could get an extra year by stamping in right at the end, but they changed it a few years ago and if you re-enter in the last year they now only stamp up to the end of the visa.
The legislation introducing DTV isn't clear on what happens with entries but it does explicitly say extensions cannot go past the validity of the visa.
If I were to guess, I suspect they will only stamp up the end date of the visa. But as Adam says we'll have to wait and see what happens.