This is pretty easy to solve. If you present data by algorithm, you are no longer an impartial common carrier and are liable for the content you present. If the user decides you don’t, ala social media 1.0.
So the user opens the app - what is the first video you show them? How does 'the user decide' from the millions upon millions of videos there are? If the user can search like in Youtube then how do you rank the results? That's also an algorithm. It isn't pretty easy to solve at all.
Rank them by best keyword match from their search query, if match is equal, order them newest posted to oldest posted.
Done.