With Mint 20 you should be able to install Crossover by just double clicking the .deb installer to use gdebi. If that doesn't work you can install it from the command line by running in the same directory as the installer
We're rebels. We're misfits. But mostly, we're software liberators. And we're very, very good at what we do. We have to be. Lots of developers work with open source, but only a tiny fraction of those are good enough to get software that was designed for one platform to work on another one. We invented CrossOver software - a unique approach to cross-platform compatibility that does not require dual-boot or another OS license. We launched PortJump to help app and game developers broaden their market beyond Windows® users. And we launched ExecMode to help organizations solve really ugly technical challenges.