After almost 2 weeks of waiting and also similar emails to yours, Microsoft was finally able to cancel my stuck subscription so I could attempt renewal, which worked!
Quite a ridiculous amount of time (though Thanksgiving + Black Friday sales in the middle of all this likely did not help), but it's done and hopefully I won't have to deal with this next year. Still no clue what went wrong exactly, just that the sub got stuck in active/expired limbo and I guess even Microsoft struggled getting their system to actually cancel it to fix it.
Here's hoping that yours is also fixed soon (if it isn't already)!