@MojangSupport I double-checked my Microsoft account and I know for a fact it's the one I used for migration, the launcher keeps telling me I need to purchase Minecraft: Java Edition before I can play it

If you have trouble launching the game post-migration, remember to use the Microsoft login option & check out this FAQ: msft.it/6011ZhIlU! ^NQ

I wasn't having problems post migration, I was able to play with my Microsoft account, until today