How to make Project view (sidebar) open files on pressing "right arrow" (in addition to Enter)

Sorry for the delay in response.

Right arrow is already assigned to the Select child node, so you will have to choose if you want to open the file or expand the collapsed tree node. If opening the file is more preferable, then try the following steps:

• remove Right arrow from the Select child node in IDE Settings | Keymap.
• add Right arrow shortcut to the Jump to source action.

For more details about customizing shortcuts please refer to this Help article.