Great it is working. I also sync iMac, iPad, and iPhone … I rely on Bonjour as faster and quicker than anything else. Does require devices be on the local network, but as they are there most of the time, no problem. When I’m “out and about” changes are synced upon return.
To setup see the “DEVONthink Manual” or more details at Bonjour Simplified
Some find Apple CloudKit unreliable (as reported here in hundreds of posts). Good it works for you.]