The algorithms in use tend to watch what you do and learn from that. I have a problem with that. in a number of days.
It means that a profile is built on you. I see that as a significant privacy and security problem. Typically the algorithm not only takes into consideration what you say you like, but also what you spend time with, often learning all the wrong things.
Engagement based algorithms have a tendency to prioritize hate speech and misinformation and can also be easily manipulated.
There is just a lot of problems with this model and even thought you could in theory make an algorithm that does not do that, that is not what is being built.