I don’t think number of representatives matters as it’s mostly representative of population. If the ratios are the same then I don’t think 435 vs 4035 matters.

You are wrong on this. You should look up Reapportionment Acts. The number of Representatives does matter in an electoral system and for other reasons. A Representative from California represents far more people than one from North Dakota. This is a major power imbalance in both electoral matters and in matters of federal legislation.

The number of Representatives hasn’t been updated in a 100 years.

No, the size of the House is determined by Congress; a century ago they decided to cap it at the current number, and never increase it since then, regardless of population increase.

> I don’t think number of representatives matters as it’s mostly representative of population

That's not the case, though. A quick look at constituents per representative across states is all it takes to see how stark that is.

It's extra important because the number of electoral votes each state gets is dependent upon their number of representatives.