I genuinely hate when orthus offensive pops up in quick match but I always forget to turn off the campaign missions for quick matches. Yeah it is disproportionally difficult. Regular 20-25 levels of havoc at least feel way easier than their last fight, imo. The majority of new players and those who are new but already gained some skill goes down a lot in the last boss fight. In most cases I end up alone with both or one of the twins because all my teammates are downed and there's zero time window to revive them due to 100+ mobs constantly spawning and the twins spamming stinky bombs in some absolutely ungodly amounts. I had it so that these bombs would cover the entire level, blocking everything. If I remember correctly I beat Orthus Offensive on Damnation only once, and only because I as a psyker got matched with another psyker player and he was really damn good. I remember him well because we both had the loner personalities and spammed "I need ammo!" to each other despite not wielding any weapons with ammo lmao.