haven’t tried learning in the form of online classes if that’s what you are referring to. to complement things like test papers etc, there are apps like Peakture and ManyTutors that you can use if you encounter any difficult problems (other users will help you solve your problems) and also tons of questions with solutions to practise on (both can filter for math at say P6, Peakture sometimes can go down to topic level). i don’t think they are specific to just math problems, but these tend to be the ones that are most commonly uploaded.

i would say the best teachers i’ve seen are the ones who are able to make studying/learning more interesting. in this sense, a mixture of creativity and understanding the student’s interests, built upon a solid grasp of the topic at hand!