the ugh sounds pretty ominous and I'm curious to what period he considers late (and by implication which era does he feel U2 jumped the shark)

There are many eras where you can cut off as late period

Hell on Babble someone cut off the late period U2 as Achtung Baby onwards (which can make sense as Achtung Baby intiiate a stylistic change).

Other people say Zooropa was where it went down hill (boo to those people)

Pop is another contender and is a widely despised album (that I think is somewhat unwarranted)

Then there's All That You Can Leave Behind which was when U2 became a nostalgic act which is a reasonable point for people to start hating them even though I think they were a decent derivative group at that point

I personally think No Lines On Horizon was the shark jumping moment and Songs Of Innocence was a disaster