I've seen a lot of issues reported but don't recall that one.
Hi, magenta2839269 -- I don't blame you for your frustration. Thank you for joining the Community and reaching out here! We have a few users reporting a similar experience here: Poor LTE Signal after updating to iOS 11. At this time, we don't have a known issue listed for the update, but if you could take a peek and chime in on that thread, we're monitoring it and will update there if anything changes on our side. I'm going to lock this thread so that we can keep all of this feedback in one concentrated location. Thank you again!