Mmm interesting. I have not hat any issues with rolling back and snapshots. Even though I do use nvidia. Configuring flathub shouldn't be too difficult I think. But I don't use a DE eather
So even if you like or dislike pewdiepie. I think him showing of Linux is good. Getting more people to realize Linux exist and is a viable alternative to Windows or Mac is a good thing.
You can route things over ssh like RDP for example. Used that a few times to remote in too a desktop at home. Can't install a VPN on most company and school devices. But ssh is build in to windows.
Can you elaborate why you think you need much more PCIe network cards? Technically you can do with 1 single LAN port with all your VLANs.
You configure the VLANs on the router then make a single trunk port to a switch. then have that switch divide the VLANs on the ports you desire. this can be a L2 switch.
I do use the proprietary drivers with a GTX 1080TI. Just the default kernel though so that might change it a bit in your case then.