Backups I actually restore
A backup that has never been restored is a rumour. Mine is a restic repository on a cheap object storage bucket, one repository per machine, with a retention policy that keeps thirty daily and twelve monthly snapshots.
The important part is a calendar reminder on the first Saturday of the month: restore one directory to a scratch machine and open the files. It takes ten minutes and it has caught two real problems — an excluded path that mattered, and a passphrase stored only on the machine being backed up.
Off-site does not have to mean expensive. The whole repository is under forty gigabytes and costs less than a coffee per month. What it does require is writing down where the passphrase lives, on paper, somewhere that is not the server.