I don't remember all the details but these are the correct questions to ask. Some batts like M18 protect themselves from undercharge. But I thought M12 relied upon the tool to protect the batt.So the adapters that allow a Milwaukee battery in a Ryobi tool, how is battery management handled? Is it all in the battery or split between tool and battery. If split then one would assume Ryobi battery management is different than Milwaukee. The adapters look too cheap to be able to convert Ryobi battery management to Milwaukee.
Also some high draw Ryobi tools use a 4th contact IIRC and many adapters don't allow for that, so you're not getting full power if running an adapter in certain Ryobi tools. Again, my small brain can't retain all the details but the internet can