The Hazard3 in the Pico 2 are bigger, more capable cores than the Cortex-M0 in the first Pico, and therefore in general faster at the same clock for compiled code.

You're supposed to be able to just recompile most Pico projects to use them as long as there is no ARM assembly in it.

They are only inferior to the ARM Cortex-M33 cores in the Pico 2.