A lot of complicated answers here but no one's given you a clear and direct one. The M1 is not faster than the 2019 MP "multiple times over". It has about 50% faster single-threaded (ST) CPU speeds, and possibly a faster built-in SSD. That's it.
But then the MP was never built for ST performance—my 2019 iMac beats it there as well. Instead, the MP is faster than the M1 for multi-threaded tasks*, and you can outfit it with far more RAM (up to 1.5 TB) and a much more powerful GPU. It also has vastly more connectivity/expandability than the M1. E.g., the M1 can drive two external displays; the MP (with the top GPU option) can drive eight
Having said that, the single biggest determinant of computer responsiveness for day-to-day computing is ST CPU performance (assuming you're not bottlenecked by slow storage, which doesn't apply to any modern Mac). So in that sense an M1 Mac might feel more responsive than a MP if you don't need heavy GPU or multi-thread CPU computing.
*The M1
Ultra beats the top MP for multi-threaded CPU performance, and its GPU's are in about the same class, but that's a very different beast from the M1 (and far more expensive). And even the Ultra doesn't have the MP's expandability and connectivity -- which is presumably why Apple is building an AS version of the MP.
Connectivity, for many pros, includes being able to plug in their various PCIe cards. Here's one with a host of different audio cards:
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