Questioning if the extra etf in my portoflio actually improves expected returns or just adds volatility

I’m 36, based in Europe, with ~13 years of investing and about $1.9M in a brokerage account (tax free as I live in Switzerland where there's no capital gain taxes).

Current allocation:

70% VT

15% QQQM

15% Bitcoin

Over time I’ve already reduced both QQQM and BTC significantly, and VT is now the core.

I’m questioning whether QQQM still makes sense.

My thinking:

QQQM is basically a US tech/growth tilt on top of VT, so it’s not a truly separate return driver

BTC already provides the asymmetric / high-upside exposure in the portfolio

Adding QQQM may not meaningfully increase expected returns, but does increase volatility and regime dependence

It also adds complexity (overlap, rebalancing decisions, less clean structure)

Alternative I’m considering:

85% VT

15% BTC

Simpler structure: one global equity base + one convex asset.

Main question: Does QQQM actually improve long-term expected returns in a VT + BTC portfolio, or is it mostly just adding correlated risk and complexity?

What would you do, and why?