Currency diversification?

I came across an article from 2018 - https://www.indexologyblog.com/2018/02/14/how-global-is-the-sp-500/-, while it’s a bit dated, I doubt there was a significant shift in the values mentioned here.
The point is that 70% of the SP500’s total revenue is in USD. Whether you hold SPY/VOO or VTI (which is 65-70% US stocks, and then I would assume the non-US companies also have a big part USD revenue) it would mean that you are exposed to the USD quite a bit. Now for US citizens I don’t think this is an issue, but for us who plan to retire in Europe or Switzerland this could cause some trouble.

Is this actually an issue, or I’m just too paranoid about it? Are there ways to get some exposure or EUR/CHF assets without losing % yield on investments? Maybe for younger investors this is fine, but perhaps closer to retirement I would like to diversify this a bit.

One option would be to buy currency hedged ETFs. But they may or may not lead to better returns vs unhedged alternates. However they reduce the foreign currency exposure

Typically domestic stocks are a way to have right level of currency exposure. Thus the base case recommendation from recent paper is to have 35% domestic stocks.

Thank you! Well, it wouldn’t be the worst plan, considering the SMI does perform decently if we take the CHF into account as well. Tho I guess with my 2. and 3. pillar I should actually be close to that 35% for now.

The article is about stock portfolio though.
For bonds I guess the common advise is to always have hedged