Select all found RegEx results in Atom

I'm trying to select all of the results found by a regex find so I can modify them all (not replace them with text!), for example, making them all uppercase with Cmd + K -> Cmd + U. I'm aware that I could do them one by one via repeating Cmd + G, Cmd + K, Cmd + U, but for a large file this simply isn't practical or realistic. I'm also aware of using bash and may other scripting alternatives, I'd like to find a way to do it inside Atom, I'm happy to install an external library if needed.

Things I've tried:

1. Cmd + D, this just selects the next instance of that exact letter, not the next result matching the regex.
2. Cmd + Shift + G and alternatives (alt/right shift/ctrl), Cmd + G selects the next result matching the Regex, which is in the right direction.
3. Changing all of the selected text to a unique string, highlighting them all, pressing Cmd + Z and hoping it will stay selected, it doesn't.
4. Lots of Googling and reading though Atom discussions.
5. Reading Atom's documentation on the subject

Pressing Alt + Enter will select all instances matching your Find results. This works for RegEx search also.

Source: https://github.com/atom/find-and-replace/pull/290

On Atom 1.57 (nov 2021) clicking on "find all" selects all matching items, esc to exit the search box, then copy :)

Alternatively you can select all whit the menu -> find > select all.

On mac also selects all by pressing ^ + cmd + G.