Heads up for those who want a game controller that works well on Linux: Target.com has the DualSense for $50 USD right now.
Bluetooth, USB, motion controls, and rumble all work. The driver is from Sony and is part of the mainline kernel, so most desktop distros should have it already.
Is there input lag on these Bluetooth controllers? Is it appropriate for a game like Rocket League?
I don’t like playing with Bluetooth controllers. It’s not necessarily the amount of input latency but the inconsistency of it.
For having fun with friends Bluetooth is fine, but if possible go for a cable instead.
That said, there’s the XBox Wireless Dongle which uses the same protocol as an XBox. The latency is minimal like a cable, and it does support up to 8 XBox Wireless Controller.
Sadly the Linux support isn’t perfect but the xone kernel driver sees regular development.
https://github.com/medusalix/xone
I think it depends on your computer’s Bluetooth module. I haven’t noticed an input lag problem with my DualShock on either of two computers, but some people with different hardware have reported lag until they switched to a different Bluetooth dongle.
YMMV, though. I have no experience with Rocket League.