First, it is unlikely you will find flooring to perfectly match. You should mix up all the boxes of laminate flooring because of possibiliites of slight mismatches between runs. Not likely you will find the same on a new that will match a worn installed.
Now, depends on if you want the same colors. For example, a maple in one and a dark walnut in the other room. Quite a contrast. IF the contrast is great, you probably want a dramatic change, so from light to dark should work. If however, you want them to be similar in color, you may want to add a dark strip between the two to make the change more pronounced, kind of quartering off the room. A line in the sand if you will.
IF you want it to look like one continuous area, then you need to pull up the dinning area and replace it all at the same time. Otherwise, you won’t get the feel visually that you are trying to acheive.
only if the rooms are separated by a door will it work to have mismatched flooring.
I would match it as closely as is possible. You can always use area rugs and carpets to define each space.
If you cant match flooring exactly, its better to go with a completely different material like travertine, granite, slate, etc.
What you are asking is a question of personal taste. I (being a wood lover) think it’s kinda cool to bounce to contrasting wood off one another, But thats just me.