From a quick google search (to make sure I'm not just stating my memories, but actual facts) the RP2040 can toggle a GPIO at about 66MHz (via its PIOs. Otherwise a bit slower, and using more CPU). USB 1 is 1.5 or 12Mbps, so you should have no issues even if you bit bang it.

Despite the USB protocol overhead, it is plenty even for a gaming mouse. Pretty sure there's no point polling it at above 1 kilohertz or so.