There is a port of FUSE for macOS, and Apple also has a first party API for this called FSKit…
https://developer.apple.com/documentation/fskit
I know there was a port of FUSE. But iirc it requires old style extensions. Has it changed?
Per the MacFUSE documentation…
> macFUSE 5.0 supports multiple APIs for mounting file systems.
> By default, macFUSE uses the VFS API to mount file systems. When specifying the mount-time option -o backend=fskit, macFUSE will use FSKit to mount the file system.
https://github.com/macfuse/macfuse/wiki/FUSE-Backends