That would obvously help if you knew what you will do.
The first question is : What do you want to own (asset allocation) ? Your answer : mostly ETFs. Do you have any reasons not to buy the world ? In your case, no. So, convert your money in USD and buy VT.
The next question is : what about the rest of your money. You have CHF and GBP. I guess your salary is in CHF. What interest rates do you have on your accounts ? There is the concept called the parity of interest rate. If the market think a currency will go down, it will have a higher interest rate and a currency which the market think will go up will have a smaller interest rate.
In february 1971 the GBP was 10.41 CHF. In november 1977 it was 3.93 CHF. In december 1985, it was 3 CHF and so on. The exchange rate between the GBP and the CHF has “always” been the worst ever, just like the stock market hits “always” new records. Same with any currency. USD was 5.5 CHF in 1800 (I don’t know how they calculate it before 1848 but whatever). CHF was 0.8 french franc (80 old francs that became cents later.) and and now the CHF is 6 french franc (in euro).
Conclusion : you can in theory keep your money in any currency, over the long term you will end up with the same ammount, as long as you have the “market” interest rate, or even a better interest rate. People prefer their home currency because there is obviously fluctuations.