Buy Minecraft once with a Microsoft account and install it again on another?

Hi! I would like to buy Minecraft on my PC in the Microsoftstore, but my sister would like to have it too. We're both logged into the same Microsoft account on the PC and in the store. Is it enough to buy 1 time?

Yes, buying once is enough because you have the same account where you can log in anywhere.

You can both play on one account, yes. But if you want to play together on a server, that is not possible.

Yes will work.

But you can't play online at the same time.

You can log into the Minecraft Launcher on 100 PCs with the same account. I signed in with my account on 3 computers, so it works.

You and your sister can play in parallel, but you can't play on the same server with the same account. Then there would be two accounts. But as long as you go to different servers, you can play with the account in parallel.

So you can play online at the same time, but not together on one server.