What's outdated is the idea that you can get any advantage from the times you have two pair compared to the times your opponent does.
Situations like this are akin to an "I cut, you choose" situation. Hypothetically, you want to size your bet such that all possible responses lead to the same expected negative EV for the opponent and positive for you, with a layer of fuzziness so that your bet size doesn't always give away what you hold. That's what is meant by non-exploitable game strategy. Doyle's original advantage was knowing that bet sizing and fuzziness more precisely than anyone else, from a combination of intuition and calculation, and also in reading the opponent's propensity to inaccurately calculate and take advantage of that too. What's changed in the last few years is that now everyone and their bots know the proper calculations as Doyle always did - and they're also good at reading your bet sizing to correctly guess that you have the two pair.
Your description is still right for a single situation: with a stack advantage, yes you want to apply pressure. What's changed is the aggregation over many such situations, where your opponents have two pair just as often and play it just as well as you do.