Hidden actions – Hover effect in the list of items

I'm currently working on WEB app, which will be the main tool for the data analysts. We will have a navigation tree that displays a hierarchical data structure. Each item will need a list of actions (add/delete/refresh). Some actions are repetitive for each item in the list, some depends on the state changes and context.

Right my team is looking for the best solution: Here are some ideas:

  1. Action icons for each item on the tree - This was a very first idea. For me repeating the buttons over and over makes it look cluttered. One of the proposed solution was to divide actions in 2 groups - frequently and less used so we will have max 4 actions icons in a row (including action "more"). Still that makes the tree "busy".
  2. Hover effect - I know the hover effect wouldn't work on touch devices but this may not be the problem. I'm wandering how about new users or those who will use the app from time to time. Would that be obvious how to delete/add new action item? Maybe actions buttons should always be displyed?
  3. Option icon proposed in Should list item specific actions be hidden on default and revealed on hover or always be displyed? So we will have only one icon per row.

It seems that option 2 or 3 may require an extra toolbar with available action depending on the position on the tree (on the right).

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I'm curious about your thoughts and tested results if any. ;)

Thanks!