Several years ago CA made a post stating "you shouldn't connect more than 4 oneclick servers to an environment". Is that still true? I don't have the link, it was on some Windows 8 tile style site.
We currently have 200+ active users between 2 oneclick servers with another 2 as DR. These are connected to 22 landscapes. With the addition of Docker images it makes it easy to stand up more.
As per my experience, I implemented Spectrum DSS with 6 one-click servers with Spectrum 10.2.1 setup.
I am not sure with the maximum recommended one-click connections, but the number is definitely more than 4.