Hey, I noticed today that I'm having the same issue. No matter how many times I refresh, as well as checking my XBox account, the Minecraft launcher continues to act as if I never purchased Minecraft. I believe there may be something going on with the Microsoft API, or some part of their services are down today. They may fix it in a few days.
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EDIT: I seem to have found the solution to my own problem, it was due to me using the wrong email to sign into the Minecraft launcher since I have multiple Microsoft accounts but only one of them had my Minecraft purchase. Maybe try using another account if you have multiple and see if that resolves your problem too.