Diversification means owning things that do not all fall at the same time. Sixty large caps in one fund is diversification within equity. Equity plus debt plus gold is diversification across assets, and that is the kind that protects you in a crash.
Owning five equity funds that all hold the same twenty large companies is not diversification; it is the same bet five times, with five expense ratios. Check overlap. Crowwd's look-through shows you exactly which companies you hold across all your funds and where they repeat.
A diversified portfolio will always have one part that looks like a mistake. That is the design. If every holding is winning at the same time, they will all lose at the same time too.
If nothing in your portfolio looks wrong this year, nothing will protect you next year.