I use Immich, but saved me money it has not. Unless you actually go through the "Backing up your photos" step, you _will_ lose your photos, it's just a matter of time. And if you're like most people, that is probably not acceptable. And by the time you do the math for the cost of your backups, you'll find Google Photos pricing is actually pretty good. Still worth it, imo.
is nas + backup to amazon glacier a good solution?
If you write 2 additional disks per year, this is a $500 initial investment plus $20 per year. Compared to Google's "AI Plus" plan you break even in year 5, assuming Google keeps pricing flat.
Of course you don't get any cloud access or similar.