There are a lot of options to work for a company that builds free software now, and not necessarily fangs / gafam. Many of those companies are struggling to fin

There are a lot of options to work for a company that builds free software now, and not necessarily fangs / gafam. Many of those companies are struggling to find people. And now, you can often even join remotely. It might be paid less but still very comfortable. You mentioned exclusively, that's true that you might have to write custom, closed code for customers at many of those companies. But that's still better than exclusively working on non free software.