are you aware that bjerg has a 33% win rate on viktor using the "standard" core/lich bane build?
tell me whats more important, being like the pros, or actually turning out wins?
im telling you, core/lichbane are just bad on viktor, sure he might chunk hard, but it doesn't 100-0 forcing you to wait for CD's, but CDR + poke oriented viktor DOES net kills due to the availability of laser + poke beforehand. (putting them to 50% poking with laser, then all ining them)
when you rush core, you have the option to either poke, and force them out (which is good dont get me wrong) BUT ITS NEVER enough to 100-0. and often times you have tons of down time to get harassed for free. being more wave clear oriented.
or you can go for CDR and have the option to do both, wave clear and poke at your discretion.
the double dorans glip/zhonya combo is extremely effective at giving you ample AP to wave clear, and survive tough enemy lanes, it is at the expense of damage, but you stop feeding and you have a much much better late game than they do as viktor when you do then build your core/rab cap/void as finishing items.
please, just try this build once
ap pen/scaling health/MR (alternative 15% scaling CDR if you're confident like i am) /AP quints
double dorans -> hex tech revolver -> sorc boots/glip -> zhonyas -> core -> morello -> rab cap
(interchange or replace morello glip and zhonyas as needed, consider replacing morello altogether with void, definitely if you take cdr blues)
you may replace glip with chapter/codex -> morello for more passive and less engage oriented laners, such as veigar, vlad, anivia, sol, ahri etc. if so dont bother with glip and then pick a new AP item to build. banshees veil is alright, but typically not enough AP, consider ludens.
you dont need double dorans if you start morello over glip.
its up to you if you're confident in lane. if you dont feel the lane is in your favor build glip and turtle it out.