I first came in contact with UNIX as I installed OpenSolaris at high school in 2009; I've played with it and OpenIndiana on and off for few years (still a heavy Windows user at the time), until I moved to FreeBSD, and later macOS (starting from Mountain Lion), which kind of nailed it.

I started using Linux around 2016, partially due to curiosity, partially due to lacking hardware support on BSD. First I went with Slackware, then Arch, Void Linux, Gentoo, RHEL, up to embracing Slackware again few months ago. In the meantime, I began using pkgsrc (on OS X, Linux and illumos first, then NetBSD as a natural consequence), and NetBSD ended up became my main system, both on server and desktop.

I'm infamously uncomfortable with mainstream dpkg/systemd distros (and honestly Linux in general) and not infrequently would I feel lost when friends ask me for help with Ubuntu.
Somehow I ended up spending much more time on BSD and Solaris than I did with Linux (I'm not involved in IT professionally) and this often puts me in a strange situation whereby I may like as a BSD guru :-P, while I don't even know how snap/flatpak/docker work (or even bash tbh). This tells something about the fact that competence is really just a matter of habit, dedication and time invested, and that nothing is to be taken for granted.