One pro of the LCDs is that I'm moderately sure they don't flicker (PWM) as (bad) as the OLED ones would.
Source: 99% of oleds cause terrible eye strain. Flicker affects people even when they don't realise it (studied for office workers during the CFL era iirc.)
That must be a small percentage of the Steam Deck userbase that's impacted by this as I have the OLED model and it does not flicker or cause _me_ eye strain, even when at the absurdly low brightness levels it can reach.
I don’t think you quite understand what a “source” is.
I'm someone who's fairly sensitive to PWM. Have tried and returned iPhones, Pixels, and similar. Steam's OLED doesn't bother me. I think it's the same screen as the Switch OLED which also doesn't bother me. Wish Apple and Google would buy from that supplier.
But in general you're correct. When given a choice, I'll generally buy IPS when I can.