from Munich - with 1-2 days - what is the most beautiful mountain area to go to?

Mittenwald

Mittenwald; Garmisch (Zugspitze), Wendelstein (train to Osterhofen, from there accessible by cog railway and cable car), Spitzingsee (train to Fischhausen-Neuhaus then bus; easy hikes), Walchensee (train to Kochel, then bus. Cable car from Urfeld up to the Herzogstand, beautiful hike over a ridge with great view of two lakes - needs sturdy shoes). Lenggries / Brauneck cable car (train to Lenggries, then bus). Tegernsee / Wallberg (bus to Tgernsee, then bus to Wallberg cable car station).

I really enjoyed Garmisch-Partenkirchen. I’m going back for a week this summer.

Thank you all. Seems like a person can read a lot, but it's still hard to know how to plan. I appreciate your ideas/suggestions!

My personal favourite: Oberstdorf
Website: https://www.oberstdorf.de/en/

I thought Mittenwald was a cute village with a pedestrian street lined with outdoor cafes.

I've never been able to "get into" Garmisch-Partenkirchen. Too big, busy, touristy? I'm not quite sure why.

The area north and east of there, on the BOB (Bayerische Oberlandbahn rail line) is all pretty, although not as mountainous as the area farther south. I particularly liked the area around Schliersee and Bayrischzell, which used to promote itself as the Urlaubs Dreieck (vacation triangle); it includes Osterhofen and the cable car to the Wendelstein. (Note, the cograil train to the Wendelstein comes up from Brannenburg, on the Inn river and on the rail line from Rosenheim to Innsbruck.)

I concur with Chris. The Illertal (Iller river valley) leading from Immenstadt up to Oberstdorf is all very nice, probably the closest to a Swiss mountain resort as you will find in Germany. I've spent weeks there. Also good there is the Kleinwalsertal, a high alpine valley that is actually part of Austria but is only accessible from Oberstdorf.

As is typical for Germany, all these areas are easily accessible by train from Munich.

Mittenwald.