I have unpinned edge (and two other default apps) from my taskbar several times but after every restart they reappear.
What I've tried:
checked group policies and none are configured that cause this behaviour
a supposed workaround of navigating to %appdata%/local/microsoft/windows/shell and editing the LayoutModifcation file but there is no CustomTaskbarLayoutCollection section which I can edit and no mention of the taskbar at all
checked regedit to see if there is some local config that would cause this issue - could not find one