I installed a variable font from Google fonts (Noto). When I add it, several iterations of the font are shown (i.e., various weights). When I install it, the font loads, but Maintype instantly shuts down. If I restart Maintype and uninstall it, it does that, but also instantly shuts down.
We have successfully installed several variable fonts of the Noto family, so we don’t know why it crashes on your side. Can you please provide reproducible steps?