Ok. I feel much better now ...
I had some situations like this.
Recently, I had to play some country parts for some recordings I was working on. They brought in these demos created by some guys in Nashville, and asked me to play the same parts but only make them a little different, in a new key.
The guitar parts on the demos were very well done, very cool Telecaster twangy stuff done in a kind of Waylon Jennings style.
I tried like crazy to match the parts and really struggled, playing them with a hybrid pick-and-fingers approach. I finally had to simplify my part in order to play it evenly and stay in the pocket (I hated it, as compared to the original demo)
The next day I was messing with a thumbpick and discovered that I could nail the part exactly with that approach, versus the flatpick. Too late, they didn't have time to allow me to re-cut the tracks. Lesson learned for the next time, if the part isn't comming together try changing your fingering, changing guitars, or use a thumbpick

I left that session feeling very humbled. But it's given me more things to practice for the next time if I get called back.
-- Jim