You problem is the f2l. my LL is almost the same time as yours, but i'm sub25. and I know more oll than you.
What helped my times was to scramble just the f2l slots using R, U, L and D only.
So I knew I could solve the f2l without cube rotations. That helped me to indentify the cases that I could solve without rotating the cube, and I made new algorithms to solve some cases that I rotated the cube before.
Then when you're confortable with the cases, and have a decent tps, you scramble the slots using F and B too, and try to solve it.
What helped me too was to go to speedsolving wiki and see the animations to ALL the f2l algorithms, I learned some cool tricks that I didn't think before, and started using some. It was weird in the beggining, but now its natural to me.
This training helped me cutting like 5 seconds in 1 week.
I also tried Petrus for one week to learn how to do x-cross. This helped me to indentify obvious x-crosses cases that I didn't know how to do before. hope this helps.