I came from deskview and then OS/2

Slackware

For sure. I worked in IT for a long time. After we switched from the mainframe to os/2 I ran it for a decade on my desktop while the company went to Windows. Then once I couldn’t run os/2 anymore due to newer hardware I switched to Linux. Ran it from the late 90s until my retirement 5 years ago.

I had to support it all myself but they let me since I was also the security guy and they realized that Windows sucked.