The new Nvidia app was just released officially to replace GeForce Experience and unify graphics settings in a single app. frl-toggle continues to work fine and the changes are reflected in the legacy Nvidia control panel. However, the new Nvidia app shows the global FPS limit as being "0".
I'm not sure if this is a problem with frl-toggle implementation or the Nvidia app, but it might be worth looking into if there's a potential fix.