bitcoin core – Do I need to create a new backup each time I generate a new address even with HD wallet on?

I don’t really understand this. Back then I remember there was something about how if you generated more than 100 addresses, you needed to backup because reasons. I don’t remember. I never generated more than 100 so I didn’t bother.

Point being, there was some change on the format of the wallet.dat that supposedly avoids this problem. So I was testing the latest version of Bitcoin Core. And I created wallet1.

Here I generated some addresses. I copied this file and renamed it to wallet2. Then I generated new addresses. I reopened again wallet1, and the new addresses that I created on wallet2 aren’t found on wallet1. My question is, how could I get the same addresses I generated in wallet2 to show up in wallet1 considering they share the same seed?

Do I need to create a new backup each time I create a new address? Didn’t HD solve this?

In practice what’s the point if I need to create new backups anyway?

This is always been so confusing to me. Because im paranoid im just going to keep making a backup of the wallet.dat file each time I generate a new address.