I think it's pointless fighting over which game is the peak. We can all pretty much agree the DS games are collectively the franchise at its best. Whether you like DPPt, HGSS, BW, or BW2. At that point, it all boils down to personal taste as they're all very good games.
The GBA games deserve honorable mention as well, as they only fall short of the DS games due to some transitional jank. They completely overhauled the games under the hood and it really didn't come full circle until the DS, but despite that the gen III games remain very enjoyable.
Reminder, the galarshitters want you at each other's throats. Don't let them divide you.