Lutris + GE-Proton + umu works. If you use GE-Proton as the runner, Lutris automatically uses umu to launch the game which launches within the Steam Pressure Vessel container.
You can manage GE-Proton downloads using Protonplus. The latest version, last I checked, is GE-Proton9-15.
I sure would love a modern, true sequel to Chrono Trigger. Probably unpopular, but maybe even a…gasp…MMO? (Let the beatings commence!)