build a view w designated rivals n enemies that show up in a gallery w latest inflammatory take from each one and some gauge of how the OP is doing vs the logged in user's dunk on it
and when new users onboard help them find their friends n foes by choosing from a list of colorfully named tribal identities to align w or against
increase cortisol by mixing in unpleasant & startling sounds n images when someone is scrolling especially through the replies
self righteous outrage is increased when we feel we're protecting the vulnerable or the sacred so encourage religious iconography and have a "think of the children" bot that ensures they are always top of mind
create "rewards" like the Robinhood confetti and badges and small donations to politicized charities, make sure newbie users get a taste early and then string them along so they keep logging on
maybe make the pfps bigger and add a filter to make the eyes look somewhat unfriendly n angry when viewed by a foe vs more exaggeratedly cute when viewed by a fren
also subtly adjust the fonts n colors to increase arousal and make them look "shouty" and slightly misaligned n unsettling
automatically find n link posts mentioning other ppl and quietly insert those posts into the target's so any talking behind someone's back gets back to them, but do it at some delay and with deniability- it was just bad luck that they came across the thread abt how they suck
or do the Local news thing of foreboding headlines but making it difficult / delayed to obtain the relevant details abt some novel threat, maybe like "3 ppl are talking shit abt you, earn or buy 5 tokens to see what they're saying"
train a model to predict when ppl are abt to log out in frustration and intercept them just beforehand w a burst of support from new (secretly bots if necessary) allies or an unexpected win
come up w pernicious UX details so that it is easy to do annoying things that affect others in the group, keep changing them up so there's always some new rule and someone blundering and someone intentionally pushing the annoy-a-tron button- think like hellthreads before thread mute
once all the pvp drama is going well, play innocent and insert an insipid "moment of zen" interstitial right when ppl are riled up... done correctly this speedbump will be triggering rather than relaxing
play ultrasounds (just above hearing range) unpredictably and in a discordant manner for subconscious annoyance; also use slightly mismatching colors to create jagged unbalanced patterns at the edge of perception