Having cloud backups is still really nice to have because while they do come with some new risks, they almost eliminate whole classes of errors like backup corruption.
One other important point is to avoid cloud services that cannot easily be replaced with some equivalent. You are far more likely to live longer than whatever random SaaS company you are using. In this case, you will probably have warning before it goes down, but you need to be able to migrate off of it (migration meaning no important data loss, not necessarily having a fully functional replacement) given a week's notice.
(Worried about a physical hard drive getting lost or damaged...)
There's nothing wrong with Backblaze et al. either. They may give much lower costs for bulk data. I only back up a few dozen GB so it's not worth opening another vendor relationship for me.
Somebody else suggested "hard drives at a relative's house." What's more likely, you lose S3 access—or your relative's house burns down / floods / is robbed / their kid yoinks a drive to use at school / any number of other disasters? Also, a backup should be as easy to do as possible—having to manually shuttle a drive back and forth from a remote location is probably not the best, unless you are extremely disciplined.
Myself I pay for Backblaze's Personal backup solution.
There also is Backblaze's B2 Cloud Storage (free 10GB tier) if you want something similar to S3.
Myself, I keep everything on my cheap surplus NAS (2 drive redundancy), snapshot regularly, and occasionally sync to an airgapped drive the next town over. I keep a cold copy at my parents house, but that's last-resort.
The important bit is that I've successfully trialed recovering from a total loss of my NAS and house, in case that ever actually happens :)
> Although some Apple services were still working, like iMessage (thank God) and Photos, I was terrified that more services would suddenly become inaccessible or that I would lose the considerable amount of data I have stored in iCloud.
It seems we get a weekly reminder that using someone else's computer does not remove the need for backups. Nebulous you-violated-terms-of-service claims, billing issues, an AI flagging you as suspicious, companies axing services or changing pricing, ransomware, etc are the drive crashes of this decade. Use multiple clouds, or mirror to a local disk. Do what you need to do. Just remember: nobody cares more about your data than you!