36yo – Simple ETF portfolio. Overthinking factor tilts vs simplicity. Thoughts?

I’m 36, in accumulation, living in Europe with no capital gains tax but ~25/30% tax on dividends (they are taxed at income tax rates). Goal is FIRE in my early 40s.

Current portfolio:

90% VT

10% Bitcoin (legacy position, planning to reduce to ~5% on the next run-up)

I intentionally simplified. In the past, having multiple ETFs led me to constant tweaking, rebalancing, and second-guessing, which hurt consistency and probably returns. VT keeps me disciplined and focused on savings rate.

I often see recommendations to add small-cap value (e.g. AVUV / AVDV). My doubts:

Does a 5–10% allocation actually make a meaningful difference?

At what point is it worth the added complexity?

How do you justify rebalancing without falling back into over-management?

My intuition is that simplicity has real behavioral alpha, even if it means giving up some expected return.

For an accumulation-focused FIRE investor:

Stick with VT only, or add a small, disciplined factor tilt?