Don't do dns level #1
Description
You don't actually need to manage dns here. You can simply generate nginx config from some json file with a list of sites to redirect to. Or even go wild and write javascript code inside nginx config, which seems to be allowed with some plugin or something. I don't remember how exactly. Or just edit single nginx config file without all that fancy stuff with a few repeating config parts. Also nginx has a way to randomly spread requests as a simple load-balancer and funny enough but you can also use it to pass the traffic to different sites. The problem with this LB mode seems is that nginx instead of redirects will hold open connections to these sites and increase load on your own servers instead of just redirecting and forgetting and also probably will break analytics of sites you redirect to and create CORS problems. These are problems only with LB mode and I mentioned those other ways without these problems earlier.
Or you can write in a half of an hour a simple 20 lines backend.
Either way DNS doesn't look like a good idea.
PS: that's pretty much reminded me more popular concept of webrings in the internet. You can look it up if you haven't heard it. If you'll frame this as a Typescript webring, you'll create much bigger community of developers with personal sites that share the same love to typescript.