Hi, I understand how concerning it feels to see Minecraft asking you to buy it again after owning it for years.
This usually happens because Mojang accounts were migrated to Microsoft accounts, and if your old Mojang account wasn’t migrated or was linked to a different Microsoft email, the game won’t show as owned.
The first thing to check is whether you’re signed in with the correct Microsoft account that holds the license, go to http://account.microsoft.com/billing/orders and look for Minecraft in your purchase history.
If you find it, sign out of the Minecraft Launcher and log back in with that same email.
If you don’t see the game on any of your accounts, it likely means the migration never happened, and the official policy now requires purchasing the current Java & Bedrock bundle.
Can you confirm if you’ve checked all your Microsoft emails for the purchase history, and do you remember migrating your Mojang account before December 2023?
Regards,
Aron