Multiple instances of Battle.Net loading and Lagging my PC

When i click once to load it up to play Diablo 3 or 4, up to 9 instances of it are visible on task manager and completely lag the App/Games. This started yesterday and makes playing impossible. I have even reset my Ryzen I7 to factory settings in case that was it, it wasn’t (RIP)
Please can you advise why its doing it and how to stop it? Thanks

Haven’t heard of this one. However, you can set Bnet to close when opening a game in its settings.