Armodafinil. It allows me to get into a flow state more easily, concentrate for longer periods of time (and more deeply), do necessary things that aren't exciting without procrastinating, and finish things.
That definitely has helped me, too. But I don't like the fact that I need it.
I'd prefer if I didn't, but it has few side effects and it's not a recreational thing, so I find it's similar to the Mometasone furoate spray I'm being prescribed to manage my sinusitis. I'd prefer to not need that, too, but breathing is more important.
I found long term use of Mometasone to have unpleasant side effects. Have you tried Montelukast, or spoken to an ENT consultant? A small surgical procedure eliminated nearly all of my symptoms.
I've not tried Montelukast (didn't even know about it, but I will look into it, thank you!), but I did have a surgery, which improved the situation somewhat, but only to a "I can breathe somewhat" level. I don't know its technical name, but it came with a general anaesthetic, lots of care afterwards, and a three-page invoice.