As someone who had a phase where he read a lot of LNs....
Yes, most of them are really fucking bad with infodumping. Made me stop reading Overlord even though I enjoyed the premise, but there came a point where I just couldn't continue anymore.
It was probably in one of the later volumes, where it was written from the viewpoint of some soldier dude in a castle, and everytime he looked at anything, it was like he had to reminisce the history of the entire kingdom in multiple paragraphs or something.
Dude looks at a knight, infodump how the entire knight system in the country works.
Dude looks at maids, infodump on where they are from, how they are different then normal maids etc.
Dude looks at a knight statue, infodump how they were made, from what they were made, how their significance changed over various generations and whatever.
And so on.
Mr. Author, it's cool that you thought about your world a lot, but that's not how you present it.