I see your point, but the main monster you want to Summon is Sigma. Anyway in a 20 cards deck 5 cards of a single archetype is not a bad ratio, it's 25%.
I've never gotten why people want to add more cards of an archetype just for the sake of it. If it makes you sleep better at night, you could probably add a Vylon Filament or something without hurting the deck a whole lot, but really... This is clearly a Vylon deck. The star of the show and only real win condition is Sigma.
That's basically the meta right now: "Screw Archetypes, just take these card that are good, substitute any other cards from some random archetype into the deck, and call it a deck of whatever archetype those sub cards are part of"
If it makes the deck better, do it. There is zero reason to run a bad card like Vylon Charger when you could use a much better card like Trident Warrior. It actively makes the deck much worse for no benefit.