I published a book with a publisher and their editor introduced some major typos into the book that we as the authors (co-authored with a friend and colleague) didn't have in our original manuscript! One was particularly embarrassing because it was a quote from a poem written in Farsi, and we double checked it with a friend who is a native Farsi speaker. So if it makes you feel any better, even "real" publishers can have typos!

And to echo some of the sentiments other authors have in the comments here, I didn't feel like our publisher gave us much in the way of marketing support at all. It all fell on us. It definitely led me to considering self-publishing moving forward, because it feels like the results would've been the same reach-wise, but we as the authors would have made a bit more money off the sales!