I tried this variant of JetBrains Mono and it had the perfect glyph width (reportedly -6%) for my screen and window sizes: NRK Mono Condensed from https://github.com/N-R-K/NRK-Mono. I also agree with almost all of the other modifications mentioned in the github page under “Some notable changes are:”

Now I can have side-by-side two editors plus a Structure or Project pane at the left in PyCharm while having 120 chars visible in both editors.