Spend time at Berchtesgaden or further towards Cortina ?

The Eagles Nest is one of the most photogenic landscapes that I have ever seen. Why don't you want to go there?

There are a number of different cable cars in the Berchtesgaden area that will get you great views and photo spots, and IIRC, the Jennerbahn one is right by the Königssee ferries and should be partly reopened by the time you're there.

https://www.berchtesgaden.de/en/come-view/cable-cars

Take the first Konigssee ferry, followed by the Jennerbahn. After, you'll have time for a shot of the iconic church in Ramsau and the a drive along Rossfeldstrasse.

Alternatively, or the next day, you can drive the Grossglockner on the way to Cortina.

Take the first Konigssee ferry, followed by the Jennerbahn. After, you'll have time for a shot of the iconic church in Ramsau and then a drive along Rossfeldstrasse.

Alternatively, or the next day, you can drive the Grossglockner on the way to Cortina.

Eagles Nest is definitely beautiful. I was going through few other posts and it gave me impression that I will be seeing equivalent scenery further to Grossglockner road and Dolomites. I may be wrong here, but that was reason.

As selkie mentioned, Jennerbahn will be partly open, will it be worth to reach till second stage ?

After Konigssee ferry and short Ramsau visit, if I leave afternoon, can I reach 'easily' reach Cortina, or should stay a night in between ?

We were in Berchtesgaden a few days ago and stayed 4 nights. We went to Berchtesgaden national park starts at Hintersee and hiked to Hirschbicl. If you don't want to hike, you can take the almbus 847. The bus stops along the start of hiking route. Beautiful view everywhere. My favorite spots are hungerbrucke and bindalm.

if you dont do eagles nest you can get similar views on the rossfeld road, which you could fit in even in the afternoon etc. its an easy drive from Berchtesgaden. its a toll road, so check opening times.
http://www.rossfeldpanoramastrasse.de/en/
last year we also did the bus ride from hintersee and the hike back, very nice experience.
if you do konigssee lake, an option is to take it to the end and do the short walk to the next lake, very scenic.
hope this helps.

Forgot to mention, if you do the ferry to Koenigsee, make sure you buy ticket up to Salet. From Salet, walk 15 min to Obersee, another beautiful lake with reflection of the cliff surrounding. (We hiked a little bit more to fischunkelalm, a steep one hour trail, the view was breathtaking).
So, stop at St. Bartholoma first, then Salet.

Thank you for helpful advice.