A rather big (28 ports) USB hub design consultation
There are plenty of 28+ port hubs on the market, "Manhattan", ORICO industrial grade, and even 97-port hub with 400W power supply. All multi-port hubs are built hierarchically out of 7-port hubs and combinations, so they encroach into 5-hub-chain rule, and need to be better connected to root ports to avoid refusals to connect.

The MTT function is critically important for performance reasons, especially if you need all devices to be LS and/or FS and have a lot of them.