Today I experienced some heavy lag while playing Helldivers 2 and Warframe while playing with my Wireless Xbox Controller in Steam, and I decided to make a simple compilation of things you can try so you don't have to go through excruciating internet posts.

• Toggling "Enable Steam Input for Xbox controllers, under Steam (top left) > Settings > Controller
  
• Uninstalling and reinstalling "Xbox Extended Feature Support Driver", under Steam (top left) > Settings > Controller
  
• Disabling per-game Steam Input, under Overlay > Controller Icon > Steam Input
  
• Uninstalling Bluetooth Xbox Controller driver and reinstalling it again (under Search > Device Manager > Bluetooth > Xbox Wireless Controller
  
• Disabling Xbox Game Nav Bar
  
• Installing Xbox Accessories from the Microsoft Store

Do you have any other recommendation? Anything that can help with this?
I've also seen recommended buying a Bluetooth 5.0 dongle to solve any Bluetooth-related issues, but I prefer to consider all non-paid solutions