Dataset Variables should support environment variables in paths i.e. %USERPROFILE% on Windows

There's many ways around this including introducing Photoshop's own dataset variables which can be used in other variables.

What it comes down to is that the file pathing system is limited. I'm glad it's ok for your use-case but you're not the only using Photoshop 🙂

Photoshop is cross-platform. Windows environmental variables don't exist on the Mac. This just breaks compatibility and you aren't going to see it.

The whole purpose of variables and datasets is for larger scale automation.

If you're having to manually update spreadsheets then you're defeating the purpose with mundane tasks, especially if those spreadsheets are generated elsewhere.

Photoshop doesn't know anything about shell variables. Just use actual paths, you are doing the data work in a spreadsheet app anyway with very good text find and replace tools.