What’s the Difference between the ANC for Bose QC,Bose QC Ultra & Ultra Gen 2 Headphones?

Not sure what ones to get, I want ones with the best ANC for the price, I want these specially for sound frequencies of people talking, like in an office.

I was thinking of getting the Ultras Gen 1 because I read some reviews of people saying the ANC is similar to Gen 2, just looking for some advice from people, thanks