Sorry that I didn’t elaborate initially.
First, disclaimer: This depends of course on the style of life you want to live. (and how/if your circumstances will change in the future)
Personally, I would argue that planning to fully retire for 40-50 years (if you do so at 40) with 1M could be statistically dangerous. (Even in the US)
For Switzerland, please see the discussion here on the forum whether 4% SWR is the rule to follow in CH.
And check here for how others have been thinking about their FIRE numbers (in or out of CH).
Also, here a solid analysis: FIRE? Here’s Why The 4% Spending Rule Does Not Apply to You - PWL Capital