Hey @MrDogeBro, that’s correct.
Also, snaps have $HOME set to ~/snap/< snapname >/current so you could simply use the $HOME environment variable in your snap (provided this is useful). The home interface allows access to all of the user’s actual home where the user owns the files, except for top level dot files/directories . The security-policy-and-sandboxing doc contains a detailed explanation about the environment variables available (as well as general confinement details)
Also, the system-backup provides read-only access to the system via /var/lib/snapd/hostfs.
Do you think you could keep your snap under strict confinement and make use of some of those interfaces instead? This way you can enjoy all the benefits of a stable runtime environment which classic snaps have.
As mentioned above, snappy-debug could help you understand the missing interfaces while troubleshooting.