I have been using Fira Code extensively and also writing texts. Both in English & in Greek, both spotting my mistakes and reading what I'd written improved within minutes of first trying it out. I may give JetBrains Mono a try as well, though I really am taken with Fira Code.
Unfortunately I have yet to find the perfect general purpose font to use in general. Ubuntu fonts do come really close to being perfect.
Whenever I try the winning font (b612, fira mono), I always go back to Liberation Mono.
Playing that game though ended up with liking Roboto Mono the most, Fira being a close second.
1) Looking at the font names I eventually picked my favorite/workhorse: IBM Plex.
2) With hidden names, I picked Courier Prime, which I disliked at first sight.
3) Again with hidden name, I picked Cousine, which looked alright in the simulator but had lines that were too strong and even on my more contrasted color scheme. I prefer fonts with varying line widths, which the game didn't really detect -- it was mostly unreadable versus readable.
But Deja Vu Mono is notably absent and I still prefer that.