Printer is not working. Problem started after BIGSUR upgrades.

When you post a question requesting a recommendation, at minimum, tell us the printer make and full model name/number. Without that information, your post is just rhetoric with no means for us to help.

We always recommend checking for vendor printer/scanner support for the upgrade operating system before the upgrade. If the vendor drivers are incompatible with Big Sur, or the vendor has dropped support for the device, then you have a paperweight unless the device is networkable and supported by Apple's built-in AirPrint technology.

That mode is AirPrint compatible and should be able to be used wirelessly. Check the user manual on how to set it up for WiFi printing.