I am going to bank another 80k or so miles into Asiana in 2021. That will get me enough for a 1st class long haul return redemtion to take in 2022/3. I don't think the merger will complete quickly enough to derail that plan.

Next year I have several business class long hauls planned that will probably be on ET or TK. Those will get me Elite at least on TK Miles & Smiles and I don't need status for those as are in J anyway. I will still have Oz Diamond (Gold) for any economy Star Alliance flights I have to take next year. I don't mind crediting those Y flights to Oz even if the miles go to waste as the miles accumulated in Y are generally peanuts.

Once I get Elite (Gold) next year on TK, I will then become a Miles & Smiles FFer and will credit all flights to TK and will ditch Asiana.