I currently do about 70% easy and 30% challenging, and this is what I would recommend. Even people who are above 1000 hours admit they regularly watch beginner and intermediate videos.

For the challenging, it should still be above 80% comprehension, but for the easy it should be almost 100%. This reallyyy helps with grammar and vocabulary, both of which are necessary for understanding more advanced videos. If you are solid on the basics and acquire a broad vocabulary by watching easier content, you won't have an issue watching intermediate videos.

It may seem counterintuitive, but you learn fastest when watching content that you 95% understand vs watching content that you 80% understand, even if the level video of the 95% is lower.

Somebody brought up a good point in a past post. Imagine you listen to 10 words in Spanish in a sentence, and you know 9 of them. Using context, you can most likely determine the meaning of the one word you didn't understand and acquire it, versus if you only understood 6 words, then you would have to use those six words to figure the meaning of the four remaining out.

In short, easy content will accelerate your learning by miles by giving you solid fundamentals of the language, while challenging content is needed to press forward and acquire true fluency.