Mastodon absolutely does have a weakness of making it more difficult to find people that you want to follow based on what you have already engaged with.
And from a purely user perspective, that is a weakness.
But it's also a very distinct choice. Because having enough data to be able to meaningfully make such recommendations means having a central database of every user interaction by every user.
And it also means making choices and value judgements which, almost by definition, can not be value neutral.
If the creators of the algorithm are good, they will actually be aware of the choices and value judgements being made, if not, well... They will still be making them, just not in nearly as educated of a way.
On the whole, I really hope that we eventually come up with answers to these problems that make it possible for a user to make those choices, and to have the amount of recommendations that they want, while somehow not having anyone have the huge database of user interactions. I'm not sure if that's even possible, most especially if you assume that there will be entities on the fediverse that are fudging their data to get recommended in ways that other users don't want.