There are many interesting courses: https://www.youtube.com/@brightsideofmaths/courses
They are paid after three videos in each playlist.
Three I’m really interesting in:
https://www.youtube.com/watch?v=g6LmapJ6k70&list=PLBh2i93oe2qvnF0fCuYAFDUJJbZ-ybBlI
https://www.youtube.com/watch?v=SrhtsGd0y1s&list=PLBh2i93oe2qvHhhyzyoga6PR5LPoJEXwy
https://www.youtube.com/watch?v=O5DnbFd426s&list=PLBh2i93oe2qujVx3lY57ViMrbXqE8y0OG
