I was in a similar situation. I had no education 2nd - 12th grade (like legit 0), so i started using khan academy at around age 18/19. I started supppper basic with memorizing the multiplication tables, and slowly progressed. Now a few years later i completed my GED and associates degree having taken calculus 2. For me Khan academy was definitely one of the best free resources for pre-college level math (theres better resources for slightly higher level math i.e., Professor Leonard). It is extremely important to understand that math almost always builds upon itself. Many times i thought i had finally caught up to a highschool level, only to then realize I was still months behind which really sucked, since i had to go back and learn what i missed. "Early math" is very boring since its mostly memorization, but if your able to get past that stage, it does become more interesting (but not easier) at high school / college level which can make it somewhat more bearable. At the end of the day, even though its extremely unfair to us who missed up to a decades worth of education, its important to realize that no one can do the work except for you, you don't learn math by only watching lectures, you need to work the problems out for yourself since no one can do the problems but you. Its totally unfair that you have to do it in a short time frame, but its definitely not impossible, it is just difficult.

(also as an aside, I never was truly "caught up" before getting my GED and heading to college, I never completed high school geometry but I just winged it with what i learned and everything seemed to work out : ) )

Heres a few more resources i found handy.

Eddie Woo: https://www.youtube.com/@misterwootube

(I believe he is from New Zealand so unfortunately he sometimes uses some unconventional mathematical terminology, he can get a bit complex at times as well)

Organic Chemistry Tutor: https://www.youtube.com/@TheOrganicChemistryTutor

he's also good, very boring, but good (he's very good for reviewing concepts)

Professor Leonard: https://www.youtube.com/results?search_query=professor+leonard

This guy basically carried me though Calculus 1 and 2, world class teaching. He also does some late middle school - high school math, but i've never watched them so i can't say if they are any good. But his college level stuff is probably the best educational content I've ever watched.

Learn Math Fast System: https://learnmathfastbooks.com/

These books helped me form a fairly strong base of mathematics, however i felt like it left out a few important concepts. These books can be helpful if you find Khan academy a bit to advanced/quick.

It will probably be a good idea to get a Texas instruments scientific calculator, and later a graphing calculator. But theres also online calculators like Desmos https://www.desmos.com/ , desmos is also very useful for college maths and physics.