Just updating with what we did in case anyone needs it later:
Dec 24:
Fondue at
Restaurant Engiadina in St Moritz Dorf (Schulhausplatz) lovely atmosphere, very nice waiters, reasonable prices (I think about 30Fr per person)
Dec 25:
Pizza at the
Laudinella hotel in St Moritz Bad. Again, very nice waiters, very reasonable prices, tasty pizza, relaxed atmosphere (mostly guests from the hotel, skiers, families...). Very large selection of pizzas.
Dec 26:
Pasta at
Diamond Restaurant in St Moritz Dorf (Kulm). I think this is supposed to also be a night club. The restaurant was cozy and very well priced, good food. It was very busy at lunch time.
For tea and coffee and pastries, we went to
Hanselmann in St Moritz Dorf (around Schulhausplatz) but imo it was nothing to write home about, prices were a bit crazy for nothing out of the ordinary. The atmosphere and the location are really great though.
A random find after a walk around the lake was the Cafe at the
Eisplatz (ice rink) in St Moritz Bad. Great prices, excellent mulled wine and you can see the skaters from the restaurant... though it was mostly just children stumbling about. The atmosphere isn't the greatest, but we were cold and overall we were very happy about it.
We walked around and explored to find all these places and in short, we liked the restaurants in St Moritz Bad better than in Dorf. There's quite a few good options around the bus stop Katolische Kirche. Some were closed on the 24 but opened on the 25 and also vice versa. We didn't really need to reserve anywhere, just walked in, but we were a small group and also our lunch times were a bit unusual (around 3pm or so

).
I'm so happy I went there for Christmas! I loved the town, personally. I was warned it would be artificial, etc, but tbh it didn't bother me at all, I found it interesting to walk around all the boutiques in such a "rural" setting. Of course I can't afford them, but hey, I also can't afford them in Zurich so no biggie. The town was a little asleep on the 24th and 25th but we found ways to entertain ourselves no problem. It seemed to come back to life on the 26th.
I also was shocked at how clear and easy the German was to understand for me, a total beginner (A1) and waiters, shopkeepers, busdrivers (!) were more than happy to switch to Italian and French if I did not understand, something I wish we had in Zurich. Of course English was also widely spoken, but I managed to get by with Italian and badGerman.

I definitely recommened it... if anything for the amazing train ride! I felt like I was taking a ride in Narnia!!.