Once you get more experienced you’ll like all knits because you can do it mindlessly while watching tv or a movie.
I have a hat pattern that calls for DPNs although it says “you can always use magic loop instead”
Since I don’t own any DPNs, I decided to try out magic loop… it’s more difficult than I thought. 
I’m gonna keep on practicing until I get it right before I start my hat.
I had the same sort of issue with the way I held my needles. I have some problems with my right hand and I can’t knit or write normally. I knit for five years or so that way before I started watching some Youtube videos on different ways to hold needles. I switched to continental style and then later modified that, but all that relearning means that now I’m very comfortable knitting. I can knit for hours now, its so nice!
How long is your circular? I find ML much easier if you have a longer circ. for hats I prefer 40" because then I have a loop at both ends which eliminates any gaps/ladders for me. It ends up being more like using two circs without any chance of using the wrong one.
That being said, I know Sue and a few others like the shorter circ and modified ML. Do what works for you and don’t give up on it.
"What I really need though is a way to make an all knit stitch project less tedious – that’s the part I’m not enjoying so much! "
What helps me is to alternate complicated Aran or intarsia patterns with a project that requires straight stockinette (even st st on tiny needles). It’s the change that makes it fun.
Yes, sometimes straight stockinette can be a bit mind-numbing, but it does come in handy when you need some mindless knitting–waiting room, tv watching, car trips, etc.