Earlier quoted context omitted.
IPv4 is for machines. IP addresses were never intended for humans, which is why domain names exist.
Except that setting up domain names for devices in your network is out of reach for most humans, while IP addresses are trivial. My cheap router that I have to reboot nightly lets me bind an ipv4 address to every device on the network so I have known address for everything. There is no comparable functionality for a domain name, or a subdomain or whatever. If my ISP offered free dyndns (and there was a well-adopted g…
I am about 80% certain that in the time it took you to write this comment you could have bought a domain name, used the registrar's web-gui to input your now static IP addresses, and had a perfectly functioning DNS setup for your home.
Or, if the free DDNS is the most important to you, OpenWRT appears to natively support quite an extensive list: https://openwrt.org/docs/guide-user/services/ddns/client