It's literally faster for me to navigate through the fonts in Finder than it is to go through my library in this app.
In any case, I have a large font library, and literally every action-from scrolling to right clicking-takes several seconds, brings up the rainbow spinner, and sends my modern PC's fans into overdrive. I suspect it may have switched to Electron under the hood and that's what's causing the problem, but that's just a hunch.
RightFont *used* to work great a version or two ago.