Not sure exactly what the issue was, it might have been the fact that I used de-Googled chromium browser and not a fresh install of Brave on my HP Zbook with Windows 11 and starting the install procedure but once I did what you suggested to get back into the fastboot mode and connect the Pixel 6 again to my Kensington dockingstation and use Brave as my browser it went smooth.
Only issue I have now is that the Pixel 6 is for a friend of mine who's old Pixel 3a has a very bad screen to it. I read that there is a option to actually restore a backup from his Pixel 3a, is that true and would that also make sure that the settings as they were on his Pixel 3a will be taken over onto his "new" preloved Pixel 6?