You can store 2TB for $14 per month; to fill that with photos you'd have to shoot 0.5GB/day for 10 years.
You can spend less - Google Drive and iCloud will offer 2TB for $10/month - but they don't really want power users who use their whole quota, so they don't make things like command line / API access easy.
Likewise Backblaze has an 'unlimited' backup option - but it's desktop mac-and-windows only, and it's selective about what it backs up - only 'user generated' files.
I have 850GB in B2 across all the backups I store there and I pay around 7$ a month. Any better price from any underdog provider? I'm definetely not going to pay 10EUR/month for Google One's 2TB.
I still need to check if I can optimize B2 costs by using different tiers (I mean, these are mainly disaster recovery backups so I dont care about fast copy times)