When using a split view, one side for all my open files, and the other side for the repl, how can I keep that latter side exclusive to the repl? When I’m working in the repl and want to also view some file, I first have to remember to change the focus to the “file side” before selecting the file in the explorer. I guess this is more of a VSCode question but I imagine I’m not the only one who wants to keep their repl visible at all times.

There really is no good way to do this. VS Code even lacks the API:s allowing extensions developers to do anything about it. A workflow you can try instead is to have the output window in the same pane as your source files. Yes, always not visible while working in some file. You can then use the command Show Output/Repl Window to switch to that tab and then Show File for Current Output/REPL Window to show the file again. These two commands replace each other depending on what is currently the active editor, and they share the same default keyboard shortcut, cmd+option+c o. Another quick way to see the results from an evaluation is to Show Hower, default shortcut cmd+k cmd+i. I often have the output/repl window closed all the time and instead rely on rich comment forms, the inline display and the hover.