You might want to have a look at TextMate. Not sure if it’s a full replacement for Notepad++, but it’s quite nice.

Should run just fine with Whisky (free) or Crossover ($74/yr).

(Also with parallels, but that's a whole new price range for just using Notepad++)

Agree. Currently using VSCode, but its not really a dedicated file editor.

Have you tried BBEdit?