How do I disable systemd-controlled daemons running under user 'lp' account?

I see various systemd-controlled daemons running under the lp account Notably, the tracker service is running and trying to index files for the lp account.

$ pstree lp
systemd─┬─(sd-pam)
        ├─dbus-daemon
        ├─goa-daemon───3*[{goa-daemon}]
        ├─goa-identity-se───2*[{goa-identity-se}]
        ├─gvfs-afc-volume───3*[{gvfs-afc-volume}]
        ├─gvfs-goa-volume───2*[{gvfs-goa-volume}]
        ├─gvfs-gphoto2-vo───2*[{gvfs-gphoto2-vo}]
        ├─gvfs-mtp-volume───2*[{gvfs-mtp-volume}]
        ├─gvfs-udisks2-vo───3*[{gvfs-udisks2-vo}]
        ├─gvfsd───2*[{gvfsd}]
        ├─gvfsd-fuse───5*[{gvfsd-fuse}]
        └─tracker-miner-f───4*[{tracker-miner-f}]

For example, I see a tracker* service is running under the lp user account, and it's writing tracker database files to /var/spool/lpd/{.cache,.local}. My question is: Is there a clean way to disable (mask) systemd service units for a specific user account, if that user account is a non-login account? I'm running Ubuntu 20.04 and systemd 245 (245.4-4ubuntu3.13), in case that's relevant.