I wouldn't have considered this to be the same issue as the linked one, but it has now been resolved. The issue turned out to be an incomplete account migration. After logging out of both accounts for several hours, I attempted to migrate my mojang account again (although it still didn't say I owned the game anymore), and the Microsoft account now correctly has access to the game.
DarkWolf13
MCL-21431
I wouldn't have considered this to be the same issue as the linked one, but it has now been resolved. The issue turned out to be an incomplete account migration. After logging out of both accounts for several hours, I attempted to migrate my mojang account again (although it still didn't say I owned the game anymore), and the Microsoft account now correctly has access to the game.