My own views on that book are complex, I've read a lot of scholarship on it (both religious by Jews and Christians, as well as secular) and I am of two minds about it.
There is clear Prophetic revelation there in it and it is one of the most Islamic books in the entire Bible with a lot of connections but at the same time it's clearly undergone massive additions since the historical Isaiah (who is not doubtfully a real person), which sheds issues with taking it at face value.
My own concerns are more about it's actual authenticity rather than whether it prophecies Muhammad or not, when it clearly has some kind of overshadowing (even hypothetically if it wasn't really to Muhammad), in a much more unabashed way than if we were to apply the same alleged passages to Jesus.