I am afraid you are still a bit misled; WireGuard is exactly what they use for the demo video. In general the underlying protocol does not matter, since the vulnerability is about telling the system to direct the packages to the attacker, completely bypassing the VPN.
My understanding is that all issues are patched in the mentioned releases, the config flag is not needed for that.
The config flag has been added because supporting clients with different endianness is undertested and most people will never use it. So if it is going to generate vulnerabilities, it makes sense to be able to disable it easily, and to disable it by default on next major release. Indeed XWayland had it disabled by default already, so only the fourth issue (ProcRenderAddGlyphs) is relevant there if that default is not changed.
The bootloader is stored unencrypted on your disk. Therefore it is trivial to modify, the other person just needs to power down your PC, take the hard drive out, mount it on their own PC and modify stuff. This is the Evil Maid attack the other person talked about.
Isn’t this the point though? Like, if you spot that (let’s concretize) the trash is starting to overflow, you can either take it out right now which will take you 2 minutes and (hopefully) barely interrupt your day, or you can add it to your list of things to do. And so you get that list of 59 things by ignoring the 2-minute rule, not by applying it.
I like btdu which is essentially ncdu, but works in a way that is useful even if advanced btrfs features (CoW, compression etc.) are used.