systemd service

[Unit]
Description=Bind mount waydroid data to /userdata
DefaultDependencies=no
Before=waydroid-container.service local-fs.target
RequiresMountsFor=/userdata

[Service]
Type=oneshot
ExecStart=/bin/mount --bind /userdata/waydroid-data /var/lib/waydroid
RemainAfterExit=yes

[Install]
WantedBy=local-fs.target