I’m a developer, too, and I did shareware/donationware ages ago.

I simply paid WinRAR for their work, from one honest developer to another.

And no, I would not pay today, as this was just for a windows box I used for a job at that time, and where I needed a halfway decent archiver tool, which Windows does not supply out of the box.

I usually work on Linux, where lack of fundamental tools is not an issue.