I see. You can temporarily edit your grub before the OS loads. This should afford you the opportunity to boot into the system without EDID modifications, though im not sure if your modified EDID will still load under this scenario. If so, you may need to switch into a CLI session to undo your changes.
I use a keychron Q3 and Q0. They can be remapped / programmed through a web (chrome derivs as it requires WebHID) or desktop electron app called VIA, which at the time of writing is proprietary. I believe Vial (written in Qt) is being brought up, so that may be an option in the future.
In terms of managing the firmware, the vendor offers a first party web interface (also leveraging WebHID). The QMK Toolbox GUI is only available on Mac and Windows but you can use the CLI on Linux to get into DFU mode and flash your firmware.
Not really keen on Logitech as a company but I use Piper to program several of their G series mice on Linux. You can check the libratbag support list to see which hardware can work with it.