On Microsoft's website, it says that multiple controllers can connect over Bluetooth but that performance may vary. I tested and it's true, controllers disconnect and reconnect when using 4 of them, very unresponsive when gaming.
I tried using USB cables but the ports on my laptop are getting tired and as we all know, older USB ports get flimsy and constantly disconnect.
Then I saw Microsoft sells Wireless USB adapters, but they are 25 USD each.
I tried with older Bluetooth USB dongles I had from 7-8 years ago but they don't seem compatible with Windows 10, possibly because they are just too old and obsolete. Has anyone tried buying more recent Bluetooth dongles on eBay to connect one controller per dongle? They are much cheaper, like this one for 2.60 USD.
If that didn't work, anybody knows of a way to connect multiple controllers wirelessly?
