Having gone through many methods mentioned in this thread, I settled on Synology. 
GOALS
• 100% access to all files 100% of the time, from any device w/o space constraints or worry
• Protection (data + physical) in event compromised device (broken/stolen/lost/hacked)
• ZERO third party cloud service
• VPN friendly
• Easy to spin up if new device is added, old device removed
• Automated backup
WORKING SET UP ← All goals met, and (finally) simple.
• Synology NAS
• Resiio Sync on NAS set to 100% sync of primary directory
• Resilio Sync on each other device set to selective sync (any files I move here sync to NAS)
(laptop often at my side (home/away,) iPhone always on me, mini at home, nas at home, one day a second offsite nas backup)
This new way is so simple, works so well.
Backstory
While committed to Synology a few years back, the solution has been a journey (keeping vpn connected, working, access from local and remote, trying different systems (synology apps, 3rd party apps, vpns, tailscale, resilio sync etc) - aways something to tweak and try or fix. Hobbled along but never quite right, always tweaking and trying new options. Then took Resilio Sync to the next level on the NAS to connect the primary target directory as the source on 24/7 sync, devices on selective sync and it has been simple and smooth sailing since.
“The search is over, Resilio Sync was with me all the while.” 
NOTE: Synology NAS was not cheap. I picked up a DS220+ to try during Amazon Prime and then had to purchase drives to install. Entire setup ran around $500. Paid itself back multiple times since and was a good investment.
Worth noting the Resilio Sync, itself, while a great product, seems to have lost developer attention, somewhat drifting along on its own anymore. Forum is rather dead, doesn’t appear to be in active development…so good to know in advance…and…haven’t found a suitable alternative (ie. syncthing, synology drive etc don’t do the job as well.) Hope Resilio renews interest in Resilio Sync.