In Steve Gibson’s latest Security Now! podcast #942 available as a PDF at https://www.grc.com/sn/sn-942-notes.pdf, among other useful tech things is a discussion about SyncThing, an open source peer-to-per synch tool.
We are not users ourselves, as we just don’t have a need, but I note that Steve Gibson is, and the item includes a link to a useful YouTube video.
If you need to sync files and prefer open source, then it might be worth a look.