You might try Notepadqq (modeled after Notepad++) or Gedit. Neither are widely used on the Julia community, but (I think) they both support Julia syntax highlighting, and they meet your main criteria.
That said, I think VSCode is the best for almost anyone starting out with Julia and with an editor. It is reasonably fast for most. It’s used by 51% of folks in the 2019 StackOverflow developer survey. In the 2019 Julia user and developer survey, 31% of folks use VSCode frequently (second to Atom at 41%). In the 2019 Julia survey, if you strike out the options that don’t meet your criteria (Atom, VSCode, Vim, Emacs, Sublime Text [not open source], and Notepad++ [Windows only]), there’s almost nothing left that people regularly use for Julia.