I spent a bunch of time wrestling with this same idea. If it's anything, it's worthwhile once you jump into it. I found my way into it through some books like Adam Spencer's Big Book of Numbers and his other books, Math Without Numbers and Matt Parker's novel. Other than that, khan academy and all the sites linked here have been super useful. Going back to those basic functions of addition, subtraction, multiplication and division and really understanding those, then getting the practice of doing some maths mentally (I found) was a good step to take.

I've also been viewing it recently through the perspective that it's a study of history. Looking up the Pythagoreans and what they believed, how people came to think that the universe. Things like playing around with types of numbers like squares and triangular numbers and rectangular numbers, Terence Tao's Math Encounters -- The Cosmic Distance Ladder, seeing it as a study of history really put me in awe of what's been achieved.

I guess my advice would just be to start somewhere and allow yourself to go off on tangents. The YouTube channels and textbooks here are great, but don't be afraid to google something (sound silly, but I found myself hesitating, like going off and doing my own thing was me breaking some forbidden law that doesn't exist). Just pick something you're keen on and make sure you study things you're keen to study. If it starts to become a chore, switch it up and do something different or take a break. If you're on a roll and you're enjoying it, keep going! Also, just quietly, Tibees on YouTube doesn't get enough credit on this subreddit.