Sorry that’s the next level of optimization, maybe don’t worry about it, start with SQ + VWRL, and revisit in a year when you’re more comfortable.
I don’t think that’d be a bad decision, the biggest cost is more likely to keep delaying entering the market.
Now for the (somewhat simplified) details (but really feel free to ignore it):
- US is >50% of global market cap
- US has a withholding tax on dividend, in practice that means for an Irish ETF holding US stock, you lose 15% of US dividends. A rough approximation would 2% dividend rate * 50% US stock * 15% = 0.15% per year
- if instead of using irish domiciled ETF, you have a US domiciled one (e.g. VT), besides having lower TER usually, those 15% will be charged directly to you, instead of to the fund.
- with the DA-1 form, you can declare those direct withholding to the tax authorities and they give you the money back
So in practice the difference between VWRL vs. VT is TER difference and those ~0.15% you’re losing in taxes.
(it’s actually more complicated, I simplified somewhat, there’s also estate tax which would add paperwork to your heirs, etc.)