By recommend, I mean content you actually find to be high quality, well done, and easy to absorb and follow. By relearn, I mean I have forgotten everything I ever learned in high school.
As others have said Khan Academy has helps plenty of students so I’ll recommend another yt channel.
Has has multiple channels but this particular one, bprp math basics, goes over tricky math problems students would solve and he goes over his solutions step by step fairly well