Comment by xmddmx

Regarding Arq backup: if you are worried about using a proprietary (enrypted) and closed-source backup format in case the company were to go under, they have an open source command-line restore tool:

https://github.com/arqbackup/arq_restore

I've been using Arq for years, but I need to look into the "Glacier Deep Archive" format which is about 1/20th the cost of the fastest storage class.