I don't participate in online discussions as much as I used to even five years ago. Life has changed.
However, I was interested in a post that someone shared a link to in a new group I joined. It interested me because I use side stories tied to the main story in my Starfire Angels books. Since the Starfire has been through many experiences, they share these to teach. The discussion shared was about flashbacks and time jumping.
It got me thinking, because the OP had questioned using such devices. I remember early in learning to write that the advice was not to use flashbacks because they slow the action of the story. I disagree.
Anything goes in writing, if you can do it well and it makes sense to the story. A skilled writer makes it work for the story. What is that line from Pirates of the Caribbean--something like "Hang the code, and hang the rules! They're more like guidelines anyway." That's how I think about the "rules" of writing.
Every rule can be broken in a way that works, but that takes skill.
The only rules I follow are 1) finish the first draft, 2) editing can improve anything, and 3) if you don't like it, neither will anyone else. I guess those are more like guidelines.