My VENUE skullcandy bluetooth headphones stopped to work on Big Sur

Hello vsdeop,

Thank you for using Apple Support Communities! It sounds like your Bluetooth headphones aren't maintaining a connection with your Mac after upgrading to macOS Big Sur. You've come to the right place for help.

Just to ensure we're on the same page, were you able to successfully complete the following steps to reset the Bluetooth module, SMC, and NVRAM, or were you unable to complete any of the steps?

Reset the NVRAM on your Mac: Reset NVRAM or PRAM on your Mac - Apple Support

Reset the SMC on your Mac: How to reset the System Management Controller (SMC) on your Mac - Apple Support

Reset the Bluetooth module:

1. Press and hold Shift-Option on your keyboard.
2. Click the Bluetooth icon at the upper-right of your screen.
3. Click the Debug option in the drop-down menu.
4. Click Reset the Bluetooth module.

Additionally, we'd like to have you test if the behavior persists if you turn off Wi-Fi on the Mac and disconnect all other peripheral devices such as a display, hard drive, etc. The following resource also provides steps to ensure you've ruled out wireless interference as well:

Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

Keep us posted on the results.

Cheers!