I can't imagine the S23U being so much better than an S22U that it'd be worth waiting nearly a year for. I think we may see some improvements on the Qualcomm Snapdragon that may make the newer devices almost as fast as a flagship iPhone but do we really need faster processors yet? The 888 is plenty fast as are the SD Gen 1. The SD Gen 2 that is due in 2nd half of this year is slated to offer even grater performance.
Camera performance will continue to improve, of course, but is it worth waiting until next year for slight improvements?