I suggest keeping it simple and sticking to it. SubClub will undoubtedly release new and awesome things while you are still working on your current stack. Don’t get distracted by new and shiny things when what you have works for you. And don’t overload your mind either, that will just work against you.
Although I obviously recommend everybody buy everything in the store, I’d say you don’t need EFit right now, since the benefits you’re looking for are present in the other subs. I have noticed my eating and exercise habits improve thanks to Khan/EoG and my stress resistance thanks to the meditation habits I developed on Alchemist. My communication is improving on PCC. My learning ability is slowly improving as well.
I like Astronaut’s suggestion. I do however think you should not put emphasis on QL. Limitless code is present in all major subs. Even though it is not as strong as QL is, you will notice your learning improving once you start taking action and actually study.
So instead you could pick another multistage. Either Khan+Mogul or EoG+Ascended Mogul, since I do think you may need a little bad boy boost from the masculine man. Likely PCC since it seems to be light, fast-acting and helps with communication and Sanguine since you appear to need some positive reframing in your life. Building that meditation habit as Astronaut suggests is a good thing.
And then go back to my first sentence and stick to it.