That's really vague. How is that done?
Rejecting the premise of identity politics isn't pretending it doesn't exist, it's arguing that it shouldn't and demonstrating that it doesn't need to.
Si vis pacem, para bellum.
I wish we could just convince people that identity politics is a sure loser*, but apparently that ship has sailed. What is likely going to be necessary is to play the game such that it starts costing the other side too.
Until those who have played identity politics for 50-60 years start losing, they aren't going to give up their weapons.
In the long-term, it would be nice if we could train our children up that they are part of one large American identity, so that they could more easily reject appeals based on their other traits.
Our education system has been doing the exact opposite of that, for about 30-40 years.
If you truly do want less identity politics, it would be wise to root out the leftist control of education that has been doing everything it can to promote it.
*It's a zero-sum game. In fact, it's probably a negative-sum game. However, the people that play it win, at the cost of the people that don't. So they'll keep playing it.