The main issue that I have with Liquid Glass, is that it changes a bunch of dimensions and behaviors.
If you are writing all your apps in SwiftUI, then that's probably OK. However, the vast majority of apps use UIKit (or use a library that is ultimately based on UIKit), with AutoLayout. In fact, I'll bet that most of the really big apps are still ObjC/NonAutoLayout.
AutoLayout/UIKit is a big fat pain in the ass, but it works extremely well. It has had over a decade, to buff out the rough spots and corner cases. I can't think of a single UI conundrum that I've had, in the last ten years, that I couldn't figure out how to address with AL. With SwiftUI, I'm constantly running into "You can't get there, from here."
Most (probably all, but I have a couple of old ones) of my apps work well in any display. That means resized (usually narrow vertical) iPad windows, rotated iPhones (where a lot of the UI scrolls off the bottom, and you need to scroll for it), and resized Mac windows.
With SwiftUI, you tend to get support for that pretty much automatically, but with AL, you usually need to specifically design for it, so when the phone gets rotated, things flow into the right places, etc.
Adding all the LG borders around things like tab bar items and navbar items, changes the layout; sometimes, fairly substantially.
Right now, I'm just tossing a UIDesignRequiresCompatibility into the Info.plist, but that feels like a kludge, and I'll need to adapt, but that may take a while.