If there was a way there would be several posts on how to root the U models. Also, the devs here have looked at the Android 12 files and couldn't find a way. It is a bit back in this thread; even I asked about it. The updates are security updates, they don't change the bootloader. Only the B model is rootable, as of now.
Simply put, it is not possible as of yet. Probably won't happen.
Not being rude, but reading a bit through this thread would help. It's all discussed in this thread. Try searching Android 12.