My daughter is slow when it comes to studying. She needs lots of time to process each lesson and subject, but she puts in the time. She took Calc 1 for the first time in college when most in her class were repeating Calc from h.s. She had her book, Khan academy on the tablet, went to office hours, went to tutoring. One of the most helpful things she did was take notes for an athlete who missed class about once a week and she ‘taught’ him the lesson. Doing that she could see if she had any holes in her own understanding.
It’s hard. It takes a lot of time. Don’t go on to the next level until you have mastered the basics.