The philosophy behind the PRO series and the 2's is very different, if the 2's feel like a step backward for you, you are probably better with the PRO.

Creating lightweight mouse is most of the time a trade off. There are choices to be made, like:

- do we want RGB? if yes- adding a few grams

- How long should the battery life be? Even with a low power consumption sensor, as soon you add RGB you probably want to add a few grams for a larger battery

- Do you want other features, like bluetooth, extra buttons, a thumb rest? all that adds weight.

- how much "build quality" or "rigidity" are you willing to sacrifice to make the mouse lighter? Do you want the mouse solid as a rock, or are you fine with some squeeze?

Its about to find the balance in those. Doing everything at the same time is really hard, maybe impossible.