We have done a couple of family trips to Hotel Post Lermoos, and I can highly recommend it as it seems to tick all your boxes. It's in the resort of Lermoos, which is part of the large interconnected Zugspitzarena ski region. Nearest lift to the hotel is approx 100m.
The hotel itself is a full board arrangement, with 7 course dinners, enormous suite rooms, and outstanding views of the Zugspitz massif. The pool and spa area is also exceptional.
https://www.post-lermoos.at/en/
The village is on the direct train line from Munich, so you can actually get a train from Munich all the way into the resort (about 2 hours from memory) and the hotel collects you from the station, so you don't need a car.