If we compare the median numbers for Portland and Munich, cities that actually have enough entries to have percentiles on levels.fyi, then the median compensations are $164k vs. $84k. That's $8.7k vs. $4.2k take home. Looking at Numbeo, the equivalent of $2.5k in Portland would be $2.1k in Munich, so that's $6.2k savings in Portland vs. $2.1k in Munich.
To me, that seems pretty significant.
There are two other aspects that can widen the gap. First, at the higher percentiles, the compensation in the US grows much higher than in Germany. Second, US engineers have the option of getting a significant increase in compensation by moving to the Bay Area, Seattle, or NYC, whereas in the EU you can't really go much higher than in Munich.
The goal was to compare MCOL cities. Maybe Leipzig wasn't the right one for that, but Munich is one of the most expensive cities in Germany.
Munich vs SF, Seattle or NY might be a fairer comparison.
Switzerland generally has higher pay than Munich.
Also how hard is it to get a $168k dev job in Portland vs $84k in Munich? I think $84k in Munich is significantly easier.
I forgot about Switzerland. Arguably it's not EU, but it's still a place that EU citizens can easily go to.
Given that both Portland and Munich have 1000+ entries on levels.fyi and the given numbers are the calculated median, I'd say it's a fair assumption that getting the median comp in both locales would be equally hard.