Can anyone offer some tips to help my fundamentals?

Just started learning jazz piano maybe a month ago and am really enjoying it. I’ve played by ear for many years and have some classical training too so I guess I’m an intermediate level pianist.

Right now my teacher has me learning Misty and I can basically play all the open voicings and the melody but…that’s kind of it... I very much feel locked in to playing a rigid performance with no improvisation and part of that is because even though I know where the chord is leading, in my mind it takes me a really long time to go through *ok I’m going from AbMaj7 to AbMin7 what is the Abmin scale again? Oh yeah I remember so then these are some notes I could improvise that would make sense in that scale.*

It’s like I can hear melodies in my head but then trying to play them feels impossible because there’s like this processing delay where I’m trying to figure out where everything is going. Jazz tends to change keys frequently and this resets my frame of reference every time and I feel like I’m having to do music theory in my head for a few seconds before I can come up with something. How can I get better at sort of predicting where the music is going to lead and then quickly recognizing what notes to play? Is it just practicing chords and scales over and over? Thanks yall!