Just want to advise that Galaxy S10+ dex mode works with desk doc when I hooked it up using HP USB cable. Mouse and keyboard worked through USB too. Only issue was office apps requesting office 365 sign in.
YES clearly DeX got enhanced. I have a DeX device (the hockey puck one) and found I no longer need it, except for attaching wired peripherals, and to charge while DeXing. I also have a plain USB C to Display port cord, and that works for DeX!