Comment 37 for bug 1600622

You maybe would have more change upstream if you reported it on https://gitlab.gnome.org/GNOME/gnome-session/issues

The system could prompt to ask if you allow the application to inhibit the screen locking and suspend, but in practice you would probably want to grant that permission for your webbrowser for e.g being able to play a youtube or netfix video without interuption. It could prompt by website but then it becomes tedious, do you really want to get asked that question on regular basis by random websites you browse?

In short there is no obvious clean solution