I don't think anybody would like to give you such a "spare" MC account, because: 1) if he gave you a Microsoft account: he would give you the password and access to the whole account (including e-mail ;) ) 2) if he gave you a Mojang account: when you try to login with a Mojang account in the launcher it would force you to migrate to a Microsoft account, which then you would own, so... same as the above 1) XD
I don't think you can have installed and use more than 1 version of Bedrock Minecraft, as it is an UWP application that is managed internally by the Windows 10 system, and may only be installed via Microsoft online store. Generally, Bedrock Edition is meant as a single version only, in fact - the latest one.
You wrote about Microsoft Store, so I suppose you have Bedrock Edition. I would suggest to backup your important worlds and then uninstall and install again the Minecraft application.