If you really want a feel for the Norwegian Fjords, do the Celebrity that goes to Geiranger.
We were on the last
Disney cruise that went there and if Disney ever does it again, we will go back!
I can't convince my family to try another line that goes there otherwise we would!
It is a beautiful port and the scenery sailing in and out is just unbelievable!
That fjord alone was worth the whole trip!
It is what you really envision when you think of the Fjords.
Geiranger port and sailing out:

Since you have already done Alaska, I would do the Fjords on Celebrity.
Stavanger is nice but it is basically a coastal sea port.
The main thing it has to see would be Pulpit Rock.
If you have watched the Mission : Impossible movies, that is where they shot the helicopter scenes going over the cliff
in Mission : Impossible, Fallout.