> but figure that I'd need to back up to The Cloud for me to feel less concerned about losing everything, at which point: what's the point?

You need to backup to an independent network in any case, surely? If not self-hosting with, for example, Imich, how do you assure backups of what you chose instead? I wouldn't trust a cloud service's promises to keep everything securely backed up and available to you, not because I simply don't trust cloud services but because with that arrangement they are a single point of failure so you can lose your data and your backup at the same time if something drastic happens at their end.

Things I run out there backup to home and things I host a home backup out there, in both cases via an intermediate to get “soft offline” behaviour (sources can't directly connect to backup hosts and vice versa meaning in the case of malicious damage both have to be independently hacked for me to lose both the source and the backup), with snapshots (a source can push a corrupted backup to the intermediate and the backups will happily pull it down as they'd not know, but the older snapshots would be untouched on the backups). Both sources and backup hosts could damage data on the intermediate if hacked or broken by my carelessness, but the damage can't spread further than that.