SPOILER WARNING: I tend to leave the answers as comments in the code
Kotlin solutions are in a standard Java-style project, separate from my preferred simple layout, just because IntelliJ wants it that way. Using Kotlin 1.6.0 and JDK 11 or 17 depending on the phase of the moon.
Python solutions are tested with 3.9 or 3.7 depending on where I am on this chart on any given day https://xkcd.com/1987/
Pascal solutions are written and tested in Turbo Pascal 7.0 running in DOSBox. Yes, I am serious. If I stick it out with Pascal for the harder problems I will probably switch to FreePascal at some point just for ergonomics.