I'll add my thoughts here in the hopes I can help.
What most people misunderstand about drugs is that they are almost all very *dose dependant* Getting the right dose can have a very particular effect, and that effect can be amplified or even the complete opposite of the effect at a different dose.
I do NOT think you should try stacking Ritalin with Xanax or the like. That may get you high, and you may feel great, but it won't be likely to achieve the focus and productivity you're looking for.
Instead, try cutting the dose to 5mg and see if that moderates the sketchy/angry aspects of the experience. You could even try 2.5mg with a "booster" of another 2.5 or a cup of coffee.
To me, it seems as though you just need a little shift, not a massive leap in your mindset. You've been productive before, and now you're just having a harder time for some reason. A little shift warrants a little help, not a huge slug of what is essentially long-acting pharmaceutical cocaine.
Drugs should be thought of as the seasoning, not the meal. A little salt can make a dish better, a plate of salt as your main course is going to be bad no matter what you do with it
Let me know if this advice helps!