How do I properly terminate my OA visa when planning a border run to Myanmar?

Ok...just got more complicated with Malaysia closing entry to arrival at least until 31 March. My OA visa expires on 31 March and I was planning to do a visa flight and return to get 30 day visa exemption. I am an US passport holder.

Since I am in Chiang Mai, my new plan is to head up to Mae Sai to a border run. My main question is, if I cross into Myanmar on 31 March and return on the same date, will my OA be terminated properly so I can start the new process to apply for the in country O retirement visa? Not wanting to stay overnight in Mynmar unless required to properly terminate my existing OA visa.

Edited: My main issue is related to the OA visa termination... not sure what impact if I enter back to Thailand on the same date as the visa expiration date...???... ideally, I was planning to flyout before expiration and stay in Malaysia for a couple days and return on 2 April...but, that is a big question mark at this point.