I'm in the same boat. Most jazz is just too busy and complex for me to enjoy. I like jazz ballads best. Simple and soulful music is my thing.
Like you, I found Bill Frissell and Pat Matheny to be the most listenable. While both do their share of "complex" stuff, much of their work is more accessible to me. Stanley Turrentine has an album of ballads I like a lot.
Bottom line for me is "do I feel it". Most jazz feels emotionless to me. It's music for musicians.