Notes & Combos
Just break their board and OTK.
Duality is not really necesary, it can transforma Megafleet into Cyber End and a Fortress into Cyber Twin to push for game, or if you really need it, transforms Cydra into Rampage. The funniest interaction is that you can dodge a Imperm or Veiler on Cyberdark Chimera by duality them into Armory Arm, sadly there are no legal duality Extra Deck targets for Core.
Ultimate Slayer puts a lot of work, regular targets are Fossil Knight, Armory Arm, Nova and Plat Gadget, but in a budget you can play Dark Hole or Chalice. Same for Pank.
I tested a Machine Duplication package and it really didn't do anything that I couldn't do without it, but it doesn't hurt to play, you can go +2 Cydra and +3 Machine Dupe and remove 1 copy of any between herz, nachster, cannon, overload fusion, repair plant or duality and add a second rank 5 of your preference in Extra Deck.