He scored two goals last game as well, so I agree they can't and wont blame anything on their defence, but you could speculate in Liverpool changing to a more conservative set up is doing their defence more favours than their attack. It is normal to be raised as a talking point somewhere. One year some say the best player in the world is a Liverpool attacker named Salah, next year when their approach changes Salah is unrecognisable at the same time their CB is being talked about as the best in the world. Maybe its form, maybe it's about circumstances and tactics, or maybe a bit of both. I fail to see the relevance of applauding a CB in a 0-0 game where they needed 3 points and he wasn't even the best performing CB on the pitch.
Reading this, I actually agree with you about what you've said about how Liverpool are setting up, both tactically and personnel, they have stabilised the defense at some cost to the attacking fluidity. Saying that, I don't think it excuses the attack though as I don't think they're overly stifled. Using today as a microcosm of their season, they had chances (Salah in particular) where either their bad finishing, first touch or awareness squandered the opportunity.
I think he had a very good game, you point out that they needed the 3 points but I don't think he can be held accountable for Liverpool not achieving that. He kept a clean sheet, did his defensive duties and for something that was criticised early on in his Liverpool career I thought he was positionally excellent. He dealt with several Everton attacks with really clever reading of the game combined with his physicality and didn't really put a foot wrong. With regards to the attacking side, he did go long fairly often but I thought he was pretty accurate with his long passing (whether he should go long so often is a different argument but I think it's a tactical change they've gone with) and he set up Fabinho with an absolutely golden chance in the second half that should have broke the deadlock.
As for not being the best performing CB on the pitch, I assume you're referring to Keane, who I thought was great also but I do thin van Dijk was better.