Help me pick a proposal spot! Austria, Salzkammergut region

Hi all! I will be visiting Salzburg and the surrounding Salzkammergut region in the next week or two, with day trips planned to Hallstatt, Berchtesgaden, Ramsau, Gosau and Wolfgangsee. I will be with my girlfriend and we will be renting a car for a few days to save some time/effort. We've been looking forward to this for months, so we're both really excited!

I am planning to propose to her during this trip, however I can't seem to decide on the best location to do it. I am looking for somewhere quiet, outdoors with beautiful scenery and accessible without having to hike far. With that in mind, my initial plan was to do it at Obersee, however it seems that it is not accessible during the winter months. Other options would be Konigsee, Gosausee or Hintersee.

Would love to hear from any locals or travellers who have been to the region on their suggestions for proposal locations that fit what I am looking for. Thanks in advance!