I essentially agree with Zoro being very strong before as well. AND we have to get used to the fact that simply no one will be able to defeat the main characters anymore, that is how they will rule the world.
Just to explain possible reason for disliking of Zoro recently by some people: psychologically everyone likes heroes that fail, then get back up. Zoro didn't fail in a long time*, and that might detach him from the audience. Luffy in turn did fail many times - it's the main protagonist formula and it works, your character has to fail and suffer to be liked.
I'm not really stating this as a truth or something, just a possible analysis.
*Edit: not that I remember anyways
Thing is there's this youtuber who I follow who is reading one piece for the first time ever and he comments on each arc he reads in a podcast type thing on YouTube.
He does this podcast with other youtubers who have all read one piece. Recently he did the alabasta video and he said his least favourite fight in the arc was Zoro vs Daz bones because Zoro just decided to cut steel AND THEN JUST DID IT. Of course the rest of the youtuber who know about haki later on and the thematic significance of Zoro having to learn to cut nothing to cut anything explained some of it to him and he pushed the Zoro vs daz bones one spot to his second least favourite.
Of course this is anecdotal and I'm not claiming this is universal since I for one loved that fought immediately but you can see that once again this isn't new for Zoro. Zoro does in fact win fights wit seemingly random asspulls and power jumps all the time with no exact effort on it. And this hasn't changed really.
Like I remember 6 years ago when a friend of mine had read the latest one piece chapter before i did and told me that Zoro just up and cut a mountain in half and I did not believe him. I was sure like this youtuber that that's seemingly random of a power jump with no exact build up really.
And then I read the chapter myself and realised what Oda was doing. He had Zoro make a full chapter of a plan to figure out how to deal with a tricky opponent. Then I realised this is literally the only chapter in the series that actually has a character make an actual plan of attack that the audience can follow and that actually works.
Then it was clear that Oda replaced the getting beaten up to near death of Daz bones with Pica having this tricky as hell ability. And Oda replaced Zoro learning a lesson about cutting nothing to cut anything and then pulling out a random ability with Zoro learning to use tactical analysis and leadership and then pulling out a random ability
People say Dressrosa is a clone of Alabasta and it sort of is and this is one of the points people overlook wth how Oda can make a clone of an arc and change small things that you can barely notice
I'm saying all this to once again repeat that nothing has changed really. How Zoro works and is characterised is essentially the same pre time skip to post time skip with the only real difference as there's less panel time so Oda focuses on the important parts of his character more. Really as far as I can tell, you must have just not liked a lot of pre time skip Zoro to suddenly feel some kind of betrayal post time skip. Like Zoro and Luffy are the most consistent characters in this story as far as I can tell.