Solution 1:

I recommend 3Blue1Brown's Channel. For an example, see this video.

Also The Mathologer

EDIT: I'd also like to add a newer channel PBS Infinite Series (EDIT2: Unfortunately they already stopped making videos.)

Solution 2:

You might wanna check out Mathologer.

Solution 3:

There are so many great maths channels. I was planning to set up my own channel at some point but its a work in progress. The top 6 I would recommend would be: (in no particular order)

  1. 3Blue1Brown

  2. Standupmaths

  3. Numberphile

  4. Singingbanana

  5. Mathologer

  6. blackpenredpen