Can’t reproduce the segfault on a fresh & updated install of LMDE5. The install script does misdetect the os as Ubuntu 16.04, when it should likely detect it as a Debian Bullseye derivative. Even though it’s the binary built for Ubuntu 16.04, it still works by default though.
You can edit /etc/apt/sources.list.d/zerotier.list and replace instances of xenial (or whatever code name is in there) with bullseye, then the apt update/upgrade routine to install the package. (You may need to apt remove zerotier-one first).
Beyond that, I can’t yet tell why some folks are getting segfaults