On windows if you don’t disable bitlocker, then login at least once to your outlook.com account so it can backup the key.

That’s not a bad idea, but if you are going to be using Linux then I’d recommend exporting the key and, for example, saving it in your password manager and/or on a USB stick (preferably after encrypting it). That way you can easily decrypt the partition using dislocker. Also, personally, I do not want to my encryption keys to shared with Microsoft, but that’s just me ¯\(ツ)/¯