You seem to mix that up with LGPL. With GPL the linked app also becomes GPL. With LGPL this is not the case; usually apps link to Qt dynamic libraries which is ok.

I guess that would work, the time and effort involved in getting end-users to link the application makes downloading a large Electron binary seem downright pleasant.

You can just ship your application with a dynamically linked Qt library file(s). There is no extra step for the user.

This is about LGPL

Correct, although LPGL is the primarily relevant one for Qt. Only a few relatively niche parts of it are under GPL.