How one would go about making their own YouTube video recommendation engine? [closed]

I’m looking into the possibility of creating a website that would serve as an alternative to YouTube’s video recommendations, attempting to recreate the old experience of getting lost in YouTube before the algorithm drastically changed and became what it is today.

What are the hurdles that one has to go through when building such a project? How would one pull the necessary information to use? What is the common approach when building recommendation engines? Is it even allowed by Google?

Self-research was already done, yet no sufficient answers were found.