U seriously need to lurk moar

>There is no "front page", it's not reddit.
There is a "front page" - the first page of the board index. That's always been a thing on 4chan & other imageboards, and it's even more of a thing on Heyuri since we're much lot slower (and glacial on /s/). Additionally, we have an overboard that shows all the threads on all the kokonotsuba imageboards (minus filtered ones) in one place as if they were a single board

>some posts are "promoted" or pushed forward while others are held back.
It's called age (AKA bumping) and sage, and they do exactly that... unless a thread is autosage'd, either automatically through being too old (a feature only enabled on Off-Topic as far as I'm aware) or by manual staff-san intervention. Again, these features are things on 4chan and other imageboards

>The only job a mod has is to enforce the rules and ban offenders.
We're not simply "mods" even if that's what the capcode says. Heyuri staff-san work on developing the site software, hosting additional boards/features, organizing events, and generally trying to help grow the userbase and keep Heyuri as "the place to be"

However, we do have a rule known as "No more board dominationz allowed by a single user/topic", as mentioned here: https://www.heyuri.net/#news54 - this came about because certain users were constantly posting and bringing up a certain "topic" in nearly every thread, preventing new threads from going in different directions (and eventually they just spammed the entire site with it)

>People who want to post and watch 3D content will go and watch /s
Yeah... unless they also don't want to see preteen girls in bikinis, in which case they have no choice but to stop visiting /s/ and filter it from the overboard