You can check the average daily volume on e.g. yahoo finance or other:
USD: Avg. Volume 34,189
CHF: Avg. Volume 4,816
EUR: Avg. Volume 40,969
i.e. VWRL in CHF is less liquid
There is no difference in currency ‘risk’, it does not exist.
For the rest: https://forum.mustachianpost.com/t/tax-optimisation-for-etf-investing/67