Is there a way to auto backup from iPhones?

I've set up a self hosted photo system with immich, and it works doing automatic backups of photos from the filesystem, eg using termux/cron, although it is a bit flakey. Immich also works for backup, but it's less ideal.

iPhone seems to be a lot harder, backup in immich doesn't work, it seems that iPhones have a complicated was of handling background tasks which make background backups very difficult.

Does anyone know a way of doing any kind of backup automatically, without plugging in a cable and without using iCloud?