Get active trails's siblings in menus

Question

I'm developing a custom theme using sub-theme just for learning purpose. In custom theme, I have added a custom block in which I need to display main menus' sub items if in_active_trail. I have already tried many times and wasted a lot time but unsuccessful.

1. Block should display when Level 1 is in_active_trails and it has child(s).
2. Block should not display when Level 1 in_active_trails but it has no child.
3. If any Level 2 is current page, display Level 2 and 3 menu items expect level 1.
4. Same as point 3, if Level 3 is current page then display level 3 and 2 items.

See attached image below for more understanding what I want to do.

Main Menu hierarchy

Answer 1

Here is the solution Menu Block. Install and configure it.

It works for me.