in v0.8 the copy-paste function switched from request to production, so if I copy-paste from an assembler to the IN chest, it'll copy the output product instead of the request that was the previous behavior. Could this change be a boolean settings thing?

This was an intentional change and you have co copy-paste from the chest to the assembler to copy input products. Does this work for you?

The new changes takes a while to adapt as they're not intuitive, but you should add it into the information page of the mod so others would know how to use this feature.

Good call to add this to the docs. The way I visualize it is that the copy-paste behavior follow the direction of items.

So if items flow from the chest to the assembler, you copy from the chest and paste to the assembler.
If items flow from the assembler to the chest, you copy from the assembler and paste in the chest.

It took a little bit for me to adjust, but now that I'm used to it, it saves me a TON of time so I don't have to constantly provide items from chests.

Does this make sense to you?

Sorry but not the way it made for you.
Considering the item flow as Ctrl+C marks the start point and Ctrl+V the ending point, if you copy things from assembly to the chest it'll copy the content of the assembler into the chest, since that's the default "copy-paste" design. Alternatively, if you copy things from the chest into the assembler, you would either:
1) try to find a recipe that matches most of the contents of the chest to autoproduce something.
2) clear the assembler recipe listing if the chest is empty.

Since it copies content from A to B that would be the logical flow of the action for me.

Your idea is counter intuitive because the above is the default copy-paste behavior, since it was invented for computers but I also understand the way you pictured the flow: You set A and B as fixed points where A will always be the source and B will always be the destination, A being Assembler or furnace or chemical plant or anything that produces something and B will always be the IN chest. The starting point of the Ctrl+C will determinate the logic flow instead of determinating the starting point of the copy content, meaning if you start the flow with the assembler, it'll mean A Output into B, the other way, B Output into A.

Takes a while to get used to that but its not wrong, its just different. If you document that, you would reduce the ammount of ppl bugging you asking about this lol

I did update the docs to document this behavior. Good to know that it might not be intuitive for everyone, but at least the behavior is consistent and documented. A setting can always be added to flip the order if needed.