You’d also want to be looking at the error rate and the fees tbh.
Vanguard’s tends to be more accurate than ishares, though not always.
The other thing to consider is that sector etfs tend to have higher fees, most are rocking charges of 0.65% or within the range of 0.40-0.80%.
You need to consider, do these sector etfs offer enough growth to offset these extra charges that it would be a better investment than your global etf, which is likely to be charged at 0.22% (it does add up.)
I’d pay close heed to the sector etf make ups and their historical performance. Consider if a spiked etf is worthwhile (like inrg recently, which has dropped from its sharp spike), or whenever an etf is truly matching its definition. For example; I think one of the top holdings for robotics is Snapchat, and one of the top holdings for a sustainability fund is actually amazon.
Basically does the title match the holdings? Does it align with your own experience and understandings?
Is the sector worth more than the global market? If not, why are we investing in them?
For an example, I’m invested in wood, which is a lumber sector etf, and part of the reason I’m in it is because that etf is made up exclusively of reits (property) and lumber industry. So it nets me two for one in diversification as part of my portfolio goal. So, where do your sector investments fit? Do they perform growth wise or diversification wise?
Finally, I’d consider looking into a bond layer as already mentioned, etfs are great but you can always do with asset diversification as well. Bonds aren’t amazing, but they’re a useful asset all the same. Consider a small holding there.
Otherwise, your global/emerging and small cap is sensible and simple in my opinion, and is an ideal starting point. If in doubt, stick with those three as 100% of your portfolio for now until you’ve done more in depth research perhaps? You always have time to research and consider and you should as it is your money at risk.