> This approach might conflict with the profit models of big tech social media... Personally, I would love a smaller social network where I can stay connected with my school friends
This sort of longing for a cozy social media circles exists a lot in tech adjacent circles. However, unless you can align the needs of users with the revenue goals of the company, which in other words simply means that users pay for the pay for the product, this is not gonna happen. While you may be willing to do so, I'm sure many people would simply stop communicating with you because of the additional friction caused, especially when a free alternative exists.
Additionally, the "viral content" you speak of exists for two reasons, which I'm not sure it could be entirely solved even if you had users pay for the product.
Most people (me included) have very little intellectual capacity after work and other responsibilities, and need some easily absorbed "slop" to kill their time. I've personally tried engaging in more creative pursuits, but I can't do a good job at it at with all my energy sapped. This is where viral content, such as posts from politicians and celebrities, gain their initial spread.
I would also like to note that someone may want to follow a politician or celebrity because they think what they're doing is generally useful or entertaining, respectively.
This leads me to my second point, where even if you self-opted to not interact with viral content, I'm not sure your social circles would also follow through with the same choice. This ultimately means the platform has to take specific measures to suppress some posts based on its content or not show any of your friends' activity, both of which has disadvantages. Further, the former is in itself controversial depending upon which politician is in power and the current Overton window[1].
(Re downvotes: I'd like to know what part of all of this people disagree with.)
[1] https://en.wikipedia.org/wiki/Overton_window#