As I understand, 435 seats in the House is chiseled in stone.
The seat counts change from state to state as the population ballons & deflates over time.
I don’t think they can ADD any House seats.
Congress passed a law locking the number at 435 a century ago next year, but it can be repealed. It needs to be. Each House member represents an average of 710,000 people, more or less depending on the state. There is no way someone can effectively do that. And its only going to get worse.
The Senate represents the States interests(as originally conceived), so there isn’t the same concern there. But the House needs to be made larger. The reason it was locked in at 435 is that is the maximum the House chamber could seat. It might be time for us to undertake building a new House chamber, able to handle up to 5000 members.