I did my undergrad in math and I'm finishing my masters in math, soon to start a Phd in math. Much like you I have also heard that Alexander Grothendieck revolutionized math. I have taken some courses in commutative algebra but I never managed to learn anything, all of my exercises where completely hackable through noob methods so that's what I did.

The only thing I have been able to do similar to Grothendieck have been a couple of times I fasted with chamomille tea.