Then why run Atraxa as your commander, if proliferation isn't what you're looking to do? I'm sure there are other commanders that synergize with planeswalkers.
I do not fully understand the question. I said that other effects are better than proliferate but not that I don't need proliferate at all. That's why I also play
Karn's bastion and Atraxa, because both of them are very good proliferate cards.
But the cards you mentioned are way weaker than the cards I listed in my answer.
For example:
Contagion Engine cost 10 Mana for double proliferate in the same turn.
Carth the lion costs 4 mana for a smiliar effect and is also a blocker and a card advantage and in combination with
oath of teferi you can already ult some planeswalkers. This will cost you a total of 9 mana and is way better then the oldshool proliferate cards.
But I'm thinking to adding in some proliferate cards like
Flux Channeler or
Evolution sage since I'm trying to increase the amount of creatures in this deck to be able to block some attackers.