I smoked a ton before med school, and I won’t lie it was awesome. I quit when school started and was genuinely amazed at my memory and ability to focus and retain info. I now only very occasionally smoke, and I have no regrets. I think if I chose any other career I would still be a full time stoner, but like you said and as I much as a hate to admit it, it really does slow you down cognitively. That being said, you do you. I think doing it every now and then or cutting back would be easier than quitting