I have a few thoughts on this...I too relied on the charts..a comfort zone..I started out with a band when I was just out of high school..a 5 piece band that consisted of old guys over 40..and me 17-18..They had charts for all the tunes..I got use to using them..and in fact even in my earlier years I used fake books...I can still recall the standards in the original keys ..I swear I can visualize the printed fake book version after all the years of playing from fake books..
Here is a tip, from my experience...The year was 1990, the month July...I traveled to a regular gig with my young lady vocalist..Carol..Set up ready to start playing and NO Music book...The book with all my arrangements...In this time..I played everything live with several different keyboards...
You know what..it didn't matter..we played the gig just as always..the charts were crutches..and the truth you already know the songs...when you are forced to play without the charts you too will realize you can play without charts..
The second part of this experience..you already know chord progressions,,and you can hear what the music is doing and where it needs to go...The exercise of playing this way will develop your ear to fingers...and I promise you ..you will feel just as comfortable after a short time..and you will enjoy the gigs more..
You will also find out..you don't mind "winging" tunes..and will have a lot of fun...
My days back then were more enjoyable..I had partners ..that were professional "minded"...and were willing and capable to perform tunes off the cuff..
Today, not so much..the singers are the type that want to sound like the record, and "need" sequenced material to perform..
My current band included..
Thankfully there are still some of my girls that can handle both..adlib live and sequenced tunes too...
If you want to learn to play without the charts...Go to your next gig without the books....and say now what?..You may be pleasantly surprised..under pressure..you already can play..