I believe so although I do not use hdmi “switches” myself.
You can always go to the harmony site and check for compatibility with your devices prior to buying the hub.
As for the migration question, Samsung’s newer phones have the “new” connect app baked in.
The migration that they are referring to is that you will get a notification at some point(In the classics app) to update/ link the two passwords together. In my case this meant that my devices and such had been migrated into the new connect app, as they are now all there and controllable.
The classic app is still more flexible/compatible. Meaning that custom apps and device handlers do not work in the new connect app along with some older “features” of the classic app.
Most people still use the classic app for the time being for, and I use this term lightly, “reliability” and customization.
Hope that helps a bit.