Simple example of running an rcloned sftpd service on ubuntu/popos. place in "/etc/systemd/system/rcloned.service" then "systemctl daemon-reload" then "systemctl enable rcloned.service" and it should be up on next reboot.

rcloned.service

[Unit]
Description=rclone sftp service
Documentation=man:rclone(1)
After=network.target auditd.service

[Service]
ExecStart=rclone serve sftp --no-auth --addr :2022 \
--vfs-cache-mode full \
--vfs-cache-max-age 10m \
--vfs-cache-max-size 32768 \
--vfs-cache-poll-interval 3m \
--vfs-read-chunk-size 8M \
--vfs-read-chunk-size-limit 4096M \
--transfers 8 \
--multi-thread-streams 8 \
--multi-thread-cutoff 2048M \
--cache-dir=/var/cache/rcloned \
-vv /mnt/data 
ExecReload=/bin/kill -HUP $MAINPID
KillMode=process
Restart=on-failure
RestartPreventExitStatus=255
Type=notify
RuntimeDirectory=rcloned
RuntimeDirectoryMode=0755

[Install]
WantedBy=multi-user.target
Alias=rcloned.service