I have experience with Dokku, Flynn (also look at this if you're looking at Dokku), CapRover, k8s, and a tiny bit of Nomad.
I think CapRover has the best experience out of the Dokku/Flynn/CapRover "group". Not a huge Dokku fan. Would use Flynn over Dokku again, but I'd rather use CapRover over both.
If you're intent on using Dokku, there's a useful web console: