Brahms op 119 no 3

[ancientsolar]

Hey there!
Looking for some fingering advice on this Intermezzo.

When I start playing this piece the inner melody for the right hand has a suggested fingering of 1-2-1 etc.. but by the time I look at 3-4 etc bars.. there are no suggestions at all..

Looking at youtube, it seems that some pianists are playing the inner melody with the thumb only and the piece sounds fairly detached. (though no phrasing in this part of the score suggests that's ok

So I just wonder how you play this piece..
Melody 1-2-1-2-1 etc .. or just Thumb ~ bars 4-6  are the issue.. but the pattern is frequently repeated throughout the piece.