I notice that when I play a legato pattern like say:

7 h9 p7 p6

I always keep my index on 6 and quite quickly I always apply a lot of pressure on it which makes legato really difficult (more so than it already is for me...). Any tips on how to cut down on the pressure? I know there have been topics about this recently but I don't really know what to do for this specific case because legato does need more pressure... but not that much. Especially for a static finger.

Relax, Breath, and just practice, practice, and practice. It will come with time. Eventually it will be like you just pulling your finger straight off without any tension on the 6th fret!!