Oh, well yeah, you can do that too. In fact, you may not even need a DDNS. I don't have one for my fedi server, and I only ever had to change the IP on my DNS after we got hit by an earthquake and all of the local datacenters went out.
I choose not to do the DNS option for 90% of the things I host. Partly because my ISP has limitations on which ports can be exposed and, in general, I prefer not to expose any ports especially when I am serving up my own data.
But that's just my paranoia talking. :cat_rock_on: