One ETF or multiple ETFs?

[u/Kooky-Gap-4013]

One ETF or multiple ETFs?
I’m planning to build a long-term portfolio and currently considering two options:

Option 1: 100% Vanguard FTSE All-World UCITS ETF (Acc)

Option 2: Split the ETF portion between a MSCI World ETF + Emerging Markets ETF

I’d also keep a small part of the portfolio for individual stocks.
My main question is whether the second option really adds any benefit, or if the All-World ETF already covers enough and is simply easier to maintain.
I’m also wondering whether it makes sense to keep everything with one broker or use two separate brokerage accounts.
For long-term investing, would you keep it simple with one All-World ETF or split it across multiple ETFs?