I rewatched shrek 1 a couple years ago, and I still think it holds up very well. it's a true classic. I haven't seen any of the others in over a decade, though.
I saw some of the outrage over the facial redesigns from the new trailer - shrek does look off to me for sure; I've seen some good breakdowns about how it's almost entirely due to adjusting the eye placement (and to a lesser extent, the way the irises are rendered). I do think it was probably a mistake for them to change the face of such an iconic character in a subtle way, because it's unlikely to make the design more appealing to new viewers, but immediately looks "wrong" to anyone who's familiar with shrek already.
some are being very negative about the fact that the trailer references things like social media/shorts, and while I agree the trailer felt kind of try-hardy (really not helped by the voiceover), I think there's a solid argument that this kind of pop-culture reference was always part of the shrek formula (see picrel). I mean, come on - grumpy old shrek grumbling about and "not understanding" tiktok? it could be funny :^p
in general, I kind of hate trailers, so I don't think it's fair to judge the movie based on a single out-of-context joke, but it certainly has gotten the public reception for the movie off to a rocky start