Same problem here. I bought Minecraft on my PC, and it says "No applicable devices linked to Microsoft account" when I try to install.
If I click on "Get more info on your device list" it shows three linked devices (xbox, pc, and laptop) all displaying "No issues found".
If I click on "Microsoft Store device management", it shows all three devices linked to the store (3 devices of limit of 10).
I also checked the XBox App on my laptop, but there is nothing listed under "Games I own". I double-checked and my xbox live account is linked to my windows account properly.
I bought a game, and I'd like to play it. Why is this process a nightmare?