Jelliot,
I drove from Friedrichsaffen to Ischgl a couple of years in ago in early Feb. It took about 2 hours (using the Arlberg tunnel to be on the safe side, though the pass was open) and was straightforward enough. This was in the days when Ryanair flew there, which I don’t think they now do. Funny enough Boabski, I hired a car through Herz and also got a petrol Kia Ce’ed when I’d asked for a diesel Golf (but at least it was an estate).
A word of caution - the only problem we had was with the Vignette, which you need to drive on the Austrian motorways. They cost about 7 Euro for a week, but if you get caught without one (like we did) it’s a 120 Euro on-the-spot fine, the receipt for which only covers you for that day’s travel so you still have to buy a Vignette. You have to get one before you cross the border from Germany. Of course, I knew about this in advance but Herz could / would not sell me one at the airport. You can get them from petrol stations in Germany but in our case we left it too late, thinking there would be signs saying “you are close to the border - buy your Vignettes here” or something like that. You live and learn - my advice would be to get one at the first petrol station from the airport you come across - the Austrian border cops have heard all the stories before and have no sympathy…
That said, Ischgl was brilliant, the only down-side being the crowded (and slightly mental) main home runs off the mountain…