I'm far from an expert in these matters, but generally speaking a faster/stiffer/"tip flex" rod is better suited for Scandi style (touch n' go) or overhead casting. A slower/"full flex" rod is better suited to Skagit (sustained anchor) casting. That doesn't mean that you can't do both with the same rod. Some rods, in fact, do both quite nicely.
I think a faster "Scandi" type rod would be better than a slower rod to handle double duty, especially if you line it with a Skagit line in the heavier range of that rod's "grain window" so that the rod will flex deeper into the mid-section and beyond. As a beginner, I found it much, much easier to learn Skagit style casts first, so that's an argument for adding a Skagit line to your kit.
To confuse things further, you can Skagit cast with a Scandi line, but a Skagit line is better suited to the job if you are fishing heavy sinking heads and/or large flies.
I have essentially no knowledge of switch rods and what is good or not so good for lines there. From what I have read, there is a diversity of opinion, depending on how you are going to use the rod. Rio
, and other major line brands like Airflo (I think) make dedicated switch lines.
When in doubt, I would talk to an expert. Poppy at the Red Shed Fly Shop is a good resource and a world class nice guy. Steve Godschall (I think I spelled his name right) who posts on this board as SPG, works for a rod builder and makes his living matching custom lines to customer's rods. He could build you a line for about the same cost as buying off the shelf, and it will be "dialed in" to your particular rod.
Good luck, and welcome to the two handed game!