Additional drivers reports the wrong driver in use

Thank you for your bug report, could you attach your /var/log/Xorg.0.log?

Here it is.

the log shows it tries to load fglrx, do you have an xorg.conf configuration?

None that I've ever touched myself - I believe changing drivers tries to edit it. Here's how it looks like for me right now:

$ ls /etc/X11 | grep xorg.conf
xorg.conf.07212014
xorg.conf.07242014
xorg.conf.07252014
xorg.conf.07312014
xorg.conf.08062014
xorg.conf.10222014
xorg.conf.11052014
xorg.conf.11072014
xorg.conf.11082014
xorg.conf.11102014
xorg.conf.11112014
xorg.conf-backup-141022083201
xorg.conf-backup-141022085225
xorg.conf-backup-141022085521
xorg.conf-backup-141107125850
xorg.conf-backup-141107130443
xorg.conf-backup-141107130805
xorg.conf-backup-141107140134
xorg.conf-backup-160106082034
xorg.conf.failsafe
xorg.conf.original-0

Status changed to 'Confirmed' because the bug affects multiple users.

Similar issue here:

I was using kernel 5.4.0.42.46 with nvidia-drivers-440, installed 5.8.3, booted into the new kernel and the graphics were way worse. Software & Updates still has the radio button selected for nvidia,

see attached, this looked terrible stretched across a 3440*1440 screen.

but:

hwinfo --gfxcard
Driver Info #0:
    Driver Status: nvidiafb is not active
    Driver Activation Cmd: "modprobe nvidiafb"
  Driver Info #1:
    Driver Status: nouveau is not active
    Driver Activation Cmd: "modprobe nouveau"
  Config Status: cfg=new, avail=yes, need=no, active=unknown

Then, Selected nouveau driver, apply, hwinfo says both drivers still inactive, restarted, looks good (hi res), nvidia settings absent from start menu settings, nouveau radio button highlit in software & updates,

hwinfo --gfxcard
  Driver Info #0:
    Driver Status: nvidiafb is not active
    Driver Activation Cmd: "modprobe nvidiafb"
  Driver Info #1:
    Driver Status: nouveau is active
    Driver Activation Cmd: "modprobe nouveau"
  Config Status: cfg=new, avail=yes, need=no, active=unknown
  Attached to: #7 (PCI bridge)

So nouveau is being used, graphics problem fixed, nvidia definitely the culprit of the graphics issues which had been plaguing me for about a year. I'll file a bug with them, however part of what took me so long to diagnose this was that I thought the nouveau drivers were broken since I could only get 1024*768. I spent hours trying to fix that, to no avail. Turns out there was nothing wrong with them, they just weren't selected. I didn't know this because I didn't think to check, I just believed the radio button. Feasibly the selected item is highlit until changed in the GUI or backend by the user, but it doesn't do an internal check (hwinfo or otherwise) to confirm that the driver it thinks is selected, is selected?

Thanks

Another related issue: I manually installed the latest nvidia graphics driver (460.67) for my GPU (1080ti), tried it out, still choppy, reverted to nouveau, restarted, all good. However the 'additional drivers' pane is wrong again, saying I'm continuing to use a manually installed driver, when I'm using Nouveau. Screenshot attached. Will attach logs of whatever people need, upon request.

Edit: related to the above, I'm no longer able to use the 'Additional Drivers' GUI since it's locked onto the wrong thing and greyed out. Any help much appreciated.