It might be worthwhile to get to the level of something like “mathematics for electrical engineers”, which is reasonably easy and would cover all the math presented or mentioned on this site, including QM. It is unreasonable to shoot for the graduate level in math, unless you actually have the goal of doing a PhD in math, or unless you are a math genius. The difference in effort between the two is at least an order of magnitude (there are many more topics to cover, and each topic is harder than the one before), while the payoff difference is negligible. Well, unless (another unless) your goal is to research AGI/FAI.
Given that, have you thought through the utility of learning all this math vs doing something else equally hard and long, and possibly boring?
It might be worthwhile to get to the level of something like “mathematics for electrical engineers”, which is reasonably easy and would cover all the math presented or mentioned on this site, including QM. It is unreasonable to shoot for the graduate level in math, unless you actually have the goal of doing a PhD in math, or unless you are a math genius. The difference in effort between the two is at least an order of magnitude (there are many more topics to cover, and each topic is harder than the one before), while the payoff difference is negligible. Well, unless (another unless) your goal is to research AGI/FAI.
Given that, have you thought through the utility of learning all this math vs doing something else equally hard and long, and possibly boring?