Operator Mono (ScreenSmart) by Hoefler & Co is a beautiful font which I love so much that I paid a bunch of money for it a while back because it makes writing code even more enjoyable. But sadly it lacks programming ligatures like the ones you find in Fira Code for example.
Luckily someone took it upon themselves to create these ligatures for Operator Mono and wrote a script to create duplicates of the font files with these symbols in it.
Assuming you bought Operator Mono and thus have the original font files you can clone the operator-mono-lig repository and create your own “Operator Mono Lig” version. I tried it out and it worked perfectly. 🎉
You can find all the information on how to do it in detail on GitHub.