Suggestion

This is a screenshot of a specific feature I can't find anywhere else than GT:NH, it's a damn good feature so I suggest it's inplemented if possible, as it makes bookmarking essentially twice as efficient to use.

It works like so:
-if you just hover an item and press the bookmark shortcut, it works like it does in current JEI, as in, it just adds the item/thing in the bookmark section with no additional features.
but
-if you instead go to a specific recipe, hover any of the products it makes and press the bookmark shortcut, it will bookmark that specific recipe, displaying that recipe in a small popup on hover and allowing you to shift + S to quick fill the correct ingredients.

edit: I'm aware this is like asking for 2000 times the work, but I have to ask, if it's trivial to implement (probably won't be) and really simple (again, unlikely), please backport it to at least 1.18.2, as it is the version I use.

I'm aware I'm asking for the moon, and you have all rights to do whatever you want, it's your project, but I'd rather ask and get a straight "no" than regret not asking.

Thanks for the suggestion!
Can you please try out JEI for 1.21.1 and compare its recipe bookmark features to your request?
I think I have implemented what you're asking for but there may be some subtleties I'm missing. Let me know how it compares.

It hasn't been backported (and may not be for a long time) but at least you can try it out to ensure things work well in future versions.

I'll try it now.

After trying : Looks close enough, neat feature to be able to chose how many you want with a simple change between ctrl and shift, It would be pretty cool to be able to bookmark a recipe without having to click on a button on the UI though. if possible of course, I have no idea how these things work from a dev standpoint.

purely from the pov of someone who likes being able to streamline and optimize my crafting process, expert packs can be a slog.