My experiments with the SteamDeck's Bluetooth range issue

Like many people, I have had major issues with the SteamDeck’s bluetooth range when using a gamepad. I was determined to work out what was happening and have uncovered some very strange findings.

Hoping that perhaps someone here can explain what it all means, and maybe offer some solutions. 

TL;DR SUMMARY

• The latency occurs across all BT controllers, but ONLY WHEN IN A GAME.
• I have full range of over 5m+ (16+ feet) when navigating the steam menu, but as soon as I enter a game the range drops to about 1.5m and I can terrible input lag.
• Possibly a power management issue with the deck?

THE PROBLEM

• When trying to play a game using a gamepad over bluetooth, I get severe input lag and dropouts as soon as I am more than approx 1.5m (5 feet) away. 
• I have observed this with 2 separate PS5 controllers and 2 different Xbox One controllers.

ATTEMPT #1 –– Interference Test & Developer Settings

Method

• Turning off all wireless transmitters around the house
• Tried outside to avoid any interference
• Turned off the “Wifi Power Management” setting in the Developer settings as I read somewhere this could help.

Results

• When using Steam menus the range is perfectly normal with no reliability issues at all
• As soon as I enter a game (in my case I opened UFO 50 as it’s a nice simple game) the range drops to 1.5m and becomes extremely unstable.

ATTEMPT #2 –– Bluetooth Dongle

Method

• Connected a USB BT dongle to the deck and, using some console commands + bluetoothctl I was able to disable the built-in BT and force the controllers to use the 3rd party dongle. 

Results

• No change in reliability. 

ATTEMPT #3 –– Xbox One 2.4Gz usb dongle

Method

• I connected a 2.4Gz dongle and installed some mods following this guide in order to use the dongle instead of bluetooth. 

Results

• Constant dropouts within 1m of range, though it’s unclear if the problem is the Deck, or the unofficial drivers I’m using are a bit janky. 

CONCLUSION

• I think the Deck’s bluetooth module is perfectly fine, the problem appears to be something to do with power management or optimisation that occurs when you’re in game.
• The good news is that this is potentially fixable via a software update, but I have no idea of how to workaround it now.