It’s a joke.
UTF-16 already exists, which doesn’t favor Roman characters as much, but UTF-8 is more popular because it is backword compatible with the legacy ASCII.
UTF-32 also exists which has exactly equal length representation for every character.
But the thing that equalizes languages is compression.
Yes, a text written in Cyrillic with UTF-8 will take more space than a Roman language, easily double. However this extra space is much more easily compressed by an algorithm like GZIP.
So after compression, the two compressed texts will then be similarly sized and much smaller than UTF-16 or UTF-32.
To be fair, it is harder for some people than others.
And that’s perfectly fine. Everyone has their own strengths and struggle areas.
Find the routine that works for yourself.