Ofc cupic is good in general and does a lot of things right on seraphine and lux, but one little mechanic is starting a skillshot channel and flashing during it. I don't really play these champs but it seems a bit harder to dodge skillshots this way.

lux q flash: https://clips.twitch.tv/SpoopyAdorableBeefItsBoshyTime-MZEn2KY2ziUmnMIx

seraphine r flash: https://clips.twitch.tv/ProudTransparentZucchiniBigBrother-a44mT1A4pSdnlnrq

Others can too like ahri. I see him do this a lot in ranked games, it's probably good to be comfortable with to consistently hit these angles