i need a clear guidance on this champ

i have played sett before so long ago that back then stridebreaker had a dash and maybe before then i played sett(cant remember now if he existed back before mythics) i was really playing it well because sett was way more busted back then but now(or last season basically) whenever i try to pick him again from so long, sometimes i get lucky i stomp my laner and snowball out of control but whenever the laning turns to a stalemate(while still lacking the gold to get my stride), or a losing side for me i just cease to function(thats not only while playing sett) and i just keep pushing it trying to get my stride to be more useful although most of these cases i need miracles to win, etc. after games like these i just feel dissatisfied and lose the will to play sett again because on how punishable this champ is and i want to keep avoiding on making dumb mistakes like dying too many times doing some bs like wasting my kit just to either not deal enough dmg or to fumble it harder by missing and also i have a question about the building on sett, does he have any good armor/mr items that work well on him? i keep building the same old build stacking health and damage just to sett W bomba ppl and beat them harder etc. but die after doing that from the enemy carries ap/ad.