It's most definitely a shame that it doesn't support an external display via the dock (which kinda makes moot the fact it supports other peripherals), I've used two different docks (both requiring DisplayLink drivers) with my home Linux setup and every kernel update is a crapshoot as to whether the dock-connected displays will blink back into life post reboot, or stubbornly stay blank until I roll back to the previous kernel version and await the drivers to catch up.
As such, I kinda understand that it may be harder than expected to get working for a device like this.
Having recently setup a new GrapheneOS device, however, it means I'm less motived to change mobile platforms again. Desktop-via-dock support could have convinced me.