Personally I like the Sentinel in 2/3 the best but in 1 they don’t really have the specific niche purpose that they seem to in the sequels, since all dual classes just get half of the powers from each.
ME1 I just go full Engineer and select AR training.
It’s always AR training.
I’ve done a few different classes but think I’m better at distance so assault rifles and such are preferred. Cons like Andromeda would have been grand cos of jet packs and being able to jump in, slash, jump out again but I found ME original series a bit clunky for that.
So sometimes biotic, sometimes engineer.