With the MAX range of MSI motherboards, the bios is not only updated to run Ryzen 3000's, but the bios is twice the size of the bios on non-MAX MSI boards.
What this means is that if you update a non-MAX MSI board, your bios interface gets reduced to a less fancy looking interface to save needed space, with supposedly no loss of features you can set in your bios.
So if a newer and presumably larger bios is needed for Ryzen 4000 series, I would be very concerned if a non-MAX MSI motherboard would have enough bios memory to run it.
Even if the above wasn't a factor, Buildzoid from GamersNexus has shown that the Tomahawk has better VRM cooling and possibly better VRM's too, so I would be choosing the Tomahawk MAX, over the Gaming Plus.