Backup / Sync solution?

I am looking for a sync software with WebUI, which syncs/backup files from one USB drive to another, connected on my RPI3 with DietPI (headless). With features like schedule (weekly), sync delete option and maybe email report/logs.

I’ve already had a look on Syncthing and Urbackup, but they seem to be only working as server, not client. I also don’t need the extra features, like accessing my backuped files with my own cloud.
I’ve also tested Duplicati with Docker, which has a nice WebUI and offers exactly the options I would like to have, but I can’t copy 1:1 raw files, it only copies/snyc the files as multiple rar part archives. And the copy process is quite slow.

Rsync inside DietPI is ok, but I am missing some features…
Found Websync, which looked what I want from the screenshots, but the project is dead.

As there are many options to choose from nice web interfaces for backup servers, is there really none which works as client with the functionality of Rsync? (…can be also a docker arm image)

I am giving up on this with my Raspberry, also for other reasons I moved to an x86 pc and cloudberry backup with web ui running in Docker is exactly what I was searching for. If someone else is still searching (on an x86 machine), might worth to take a look on this software.

On the pi the closest I got was Syncthing running in two instances with Docker and nextcloudpi with local storage addon - but both options where not really satisfying.
Another alternative (but not as good) to Cloudberry on x86 would be Websync.

Hmm, webmin can do backups as well, with web UI, scheduling, local or external targets, looks like what you want on first sight. However it offers much more other things, so not that slim simple solution that you are looking for.

You mean Webmin with Syncmin Addon, yes, that was ok.
In general Webmin is really good, at the moment its the only thing I am missing a bit. I just moved from DietPi to Libreelec and now I am running everything in Docker containers. Webmin is (as I know), because of the complexity I guess, not available in Docker.