I use screen in my terminal windows. I have no trouble getting access to those.
The main graphical app I use is my web browser. I use Chrome. I click "new tab" and click "other devices" in the lower right hand part of the screen. Shows me everything I have open everywhere - desktops, phones, tablets.
I can access everything on my desktop remotely with little fuss even I have minimal bandwidth.
As for running other gui apps remotely, I just ssh -X to whatever machine I want (including ones without any desktop) and run the app I want.
I've used X11 desktops since 1990 and never really used Windows. The few times I did I found any remote solutions painful and slow even when they were nearby. Worse even than ssh-tunneled trans-Atlantic X11 apps.