i mean hell even from the start this was a really cool part of the world, bc yeah, our level 3 pcs aren't (like most dnd parties) still finding their feet, they're mostly decorated war veterans and people who invented new magic and those who've spent their lives working to be as good as they are! and it's not for nothing, brennan straight up called out in ep 4 that their exceptionalism in that regard is why julien and vaelus and thaisha survived the circle of death (when all the attendants in the house aren't even level one, so died instantly) - level 3 is what you get to after 20+ years of fight training. after decades of spellcraft. level 3 is what you get from being an 800 year old paladin.
(hannan himself, also at least that old, an active druid this whole time, couldn't have been more than about level 12 or the PWK wouldn't have worked, and i'd guess that he was somewhere more in the level 5-7 range)
and then just in the overture we saw primus use two 7th level spells on the same day (upcast bestow curse on murray, plane shift to find occtis) and a level EIGHTEEN sorcerer ability (umbral form, to steal raimond davinos' skull)
(and while i agree with you wholeheartedly that nothing shows the level of power more than the casual use of power word kill, the 5th level telekinesis on your sister just to make a point is also nothing to sneeze at)
brennan was not at all kidding when he said trying to push amariya cormoray (who is not the head of her house and not yet on primus or yanessa or otto's level) down the stairs was like starting a fight with a dragon
sundered houses are on some next level shit