Did you try higher dose. You need to take 0.35g/kg body weight for effects on brain, atleast thats the doses that are usually used in the studies. I believe your body will distribute it to your muscles before any goes to the brain, so you need to take a dose that will saturate your muscles and then have extra left over. I take 25grams whereas the usually reccomend daily dose is 5grams

As a vegan you dont get any creatine since you're not eating meat, so your body has to make it itself, which requires a ton of methylation and if you're like me and have bad genes for methylation your body had a hard time with it as it is. So by supplmenting creatine you're reducing some of that burden.

As far as sleep goes, high dose creatine has been studied to have an extermely positive effect on brain function during sleep deprevation, better than stimulants/caffine

I think the prescribed dosing for creatine and sleep deprevation is 0.35g per KG, much higher than the typically recommended dose of 5gs a day for muscle. The positive effects on the brain come at much higher doses. Which is perfectly safe for your kidneys, this is a myth (as long as you dont already have poor kidney function).

https://www.nature.com/articles/s41598-024-54249-9

https://pubmed.ncbi.nlm.nih.gov/16416332/

Say MTHFR one more time, I dare you.

Never heard of the acronym though so not sure what the mutation implies.