Did you know that VS Code added support for the same four-pane view as p4merge years ago? I used p4merge as my merge tool for a long time, but I switched to VS Code when I discovered that, as VS Code’s syntax highlighting and text editing features are much better than p4merge’s.

I also use the merge tool of JetBrains IDEs such as IntelliJ IDEA (https://www.jetbrains.com/help/idea/resolve-conflicts.html#r...) when working in those IDEs. It uses a three-pane view, not a four-pane view, but there is a menu that allows you to easily open a comparison between any two of the four versions of the file in a new window, so I find it similarly efficient.