This is why we are unlikely to see any Mac Mini called a “Pro”. To much conflict with the naming of the Mac Pro And just too much confusion all around.
I suspect PRO moniker will apply to Mini. Besides specs, Design and price tag will suffice to distinguish.
If Apple are - as rumoured - going to produce a smaller, cheaper alternative to whatever replaces the Intel Mac Pro then it would make sense for that to get either the 2x or 4x processor. In that case, the replacement for the Intel i5/i7 Mac Mini is unlikely to offer anything more than the single pro/max chips... which would still be a great upgrade from the Intel versions, especially in terms of graphics. Price points aside, the 2x/4x packages are going to be larger and hotter than the regular Max and (presumably) support 2x or 4x the TB4 ports, so they'll need different logic boards, cooling and might not suit the Mini case design.
...but trying to reason beyond that based on which models "deserve" the Pro monicker is pointless. Apple have never used "Pro" consistently in the past (... e.g. 2-port/non-touchbar 13" Intel MacBook
Pro, 10-core i9 5k iMac not
Pro...)
Let's imagine Apple
were going to start using "Pro" consistently. What do
they think it means (that's all that counts)?
They have already cast the die (see what I did there

) by calling their mid-range processor "M1 Pro". It has features that make it
better than the regular M1 for tasks like media production, 3D, scientific computing, more-demanding development, but which probably won't have much impact on general productivity/comms/media consumption workloads. It also falls short of the requirements for higher-end workstations. So that
is what Apple mean by Pro as applied to processors.
In the new Apple Silicon world, it looks like the entire range of Macs will be using M-series SoCs, there's no hard mobile/desktop distinction and the GPU, max number of ports, max RAM etc. are all pretty much determined by whether it's a Pro/Max/x2 or x4 SoC. So, going forward, "Pro" in the model name would logically imply a "Pro" or better processor. Therefore a Mac Mini with a M1 Pro processor or better would be a "Mac Mini Pro" (If the 13" MacBook 'Pro' sticks around with a non-pro M2, a dab of paint would fix something that's been inconsistent since 2016...)
...or, Apple could continue business as usual and just treat "Pro" as a model differentiator with no particular meaning. That's probably more likely - but would makes it pointless to speculate about "pro" being associated with particular processors or features.
I'm pretty sure that they're not
actually going to have machines called "Mac Pro Mini" and "Mac Mini Pro" - although we're talking about the marketing department that has already created the M2 vs. M1 Pro confusion and called a chip "M1
Max" when there are still at least two more powerful variants in the pipeline... so who knows?