The best decision for me is still to buy synology and store everything locally on Synology photos. No subscription, expandable storage, and full privacy. It is 100% worth the extra $ if you plan on subscribing for a loong time anyway
I think many people forget about this. They pay for a monthly or yearly cloud storage subscription, but forget they have to pay this amount every year for the rest of their lifes if they want to keep their data. That's why I also use a Synology disk. I also have an additional lifetime subscription at a cloud storage provider (which pays back within 3.5 years). Sure they can disappear after say 10 years, but at least I have the Synology and I got a much better deal during those 10 years and can look for something else.
Another thing, don't upload all pics you take immediately, only sync after you have cleaned out all the bad photos and near duplicates.
It's unlikely that people are using SSDs for the main storage on a NAS though, commonly just used for smaller parts (think metadata in ZFS-land for example), not for the main storage. Precisely for that reason.
SSDs use flash memory cells, which have a limited amount of writes you can do to them before they start to fail. Compared to magnetic disks in HDDs that don't have a finite lifetime of writes.
If you are mostly reading data, then no worries, probably won't affect you. But NASs typically gets a lot of writes, so you want something more durable than SSDs (in terms of writes).
Sure, if you upload 10 photos a week and never do any other reads, go with a SSD for all I care, it'll last long enough.
Solution: a RAID system with 5 reliable disks and you replace 2 of them every 5th year, and the other 3 in the following 4 years.
RAID is only useful as long as you don't suffer more simultaneous disk failures than you've provisioned for (where "simultaneous" is dependent on your time-to-repair, since if it takes you a week to replace a dead drive, then two failures in the same week are indistinguishable from two failures in the same minute, in that you've lost the entire array).
Depending on how much data you have to archive and frequency of access, it may very well be worth the cost to entirely offload opex and capex to cloud storage.
AWS Glacier Deep Archive in us-east-1 is $1/TB/month (GCP and Azure offer comparable pricing for archival storage). If you have 5x 4TB SSDs that, say, run you $200 each, and you run RS(5,3) then you're storing 12TB of data for $1000 of capex for 5-10 years. Meanwhile AWS would set you back $144/year, so the breakeven on capex alone would be if you would normally rotate your disks every 7 years.
And yes, my wife regularly looks at photos from 3,4,5 years ago, or older.
But you might still have some value in using Glacier for archival purposes and having somewhat less resilient local copies (e.g. only being able to tolerate a single disk failure, or even just JBOD).
Either way, your current approach clearly works for your circumstances, even though it'd be too fiddly for me personally.
In any case a NAS with 5 disks is probably overkill for family photos and videos, a single disk or at most a RAID0 with 2 disks over a RPi5 will be enough for many people and way way cheaper than a 2TB plan, but obviously you need to know how to and like to self-host
I personally am considering Ente right now, since having E2EE Google Photos sounds actually pretty cool, despite the fact I have a NAS (a Synology NAS, for that matter). However, my reasons to not using the NAS as you could are different: this is really the place where I store everything, so I prefer having it accessible from local network only. Not sure how you guys feel safe putting something like Synology on the open internet. (Also, I currently don't run it 24/7 anyway, but that's for different reasons, which I hope will become obsolete when I find a better place for the NAS at home.)
Isn't this why offsite backups are important?
Synology has Hyper Backup, and as you mentioned, there's also rclone.
I personally think the biggest benefit to keeping photos as simple files (and maintaining my own offsite backups) is that I'm never at the mercy of one of the SaaS's microservices being down, features being nerfed, or a company being restructured or acquired.
I do see the "peace of mind" that an automatic photo hosting/backup service gives. :) Well, one could always use them all (maintaining file backups and paying for a service like Ente) for real user-side redundancy and convenience.
I actually have 2 backups, google photos low quality backup, and the synology one.
Have you taken depreciation into account in that calculation? Compute, memory, and storage are still getting cheaper each year due to manufacturing improvements.