Yeah, you just need to set your DNS using Cloudflare. Your router doesn’t matter. Ddclient will get your external IP address, usually by querying an external server like ifconfig.me (this is all configurable), and then use the configured provider (e.g. cloudflare) to point the DNS records to your external IP. You need to configure your DNS registrar to use the Cloudflare nameservers for your domain. Then just regularly (daily) run ddclient, e.g. using a cronjob

I’m having a good experience with cloudflare, using ddclient on a cron job

To clarify: it doesn’t matter much what your router supports if you have a server with ddclient (possibly in Docker container). Then you can choose whatever provider you’d like, and there are tons of resources on ddclient.

I use:

• 3-way zfs mirror for important data like photos, documents
• snapraid for bulky and less important data like movies
• hourly backup of important data and a subset of the less important data (difficult to find movies) to a rpi with a big disk
• daily backup of the same data to a friend. We have a system where we put a hdd in each other’s server and have ssh access

Backups are done using restic

Off-site rather than offline, protecting against things like your house burning down.