I've been somewhat pulling my hair out (ok, that's a lie - I have none) figuring out a way to update a Cloudflare A name using the UDM-Pro. There's a long list of reasons you'd want to do this, but for my purposes in this instance I want to setup a VPN endpoint. Of course, static IP addresses aren't something that are common for small business users, and especially not so for home users. Setting manual DNS entries will work for all of a few days and users need something easy to remember that will update whenever the public IP address of the UDM-Pro gets updated (which could be days, weeks, or even months apart).
Ubiquiti's firmware allows DDNS updates natively within it, but the providers are quite limited, and despite Cloudflare being arguably the most requested one in the forums, they've yet to add it. I suspect this is because it's not as simple as a quick URL call with some variables like DynDNS used to be. There's some tricky ways to do this using DNSoMatic, but I'm going to be setting this up for a long list of clients, and I also really don't want to rely on yet another middleware service.