@feditips @Gargron …perhaps it can be as simple as…just a landing page with the ?most capable? 3-5 instances and then a selection of “I know what I’m doing let me pick.”

The points of concern being (in no particular order);
That the instances in the list are/can take large amounts of new users gracefully and/or have capacity to support them. These can be updated/changed over time.
And that the mobile app has only a small amount of real estate to work with.