My first 2019 Mac Pro was a 16 core 3.2ghz which would turbo-boost to 4.4ghz. I upgraded it to a 28 core W3275M Xeon 2.5ghz which also had the same turbo-boost 4.4ghz.
In my real world use, the 28 core is much faster. Then I got another 28 core 2.5ghz 28 core Mac Pro fitted with a pair of W6800X Duos. Both of them run great, I have no need to replace them yet. For all the things Apple does badly, the 2019 Mac Pro was beautifully built and easy to work on. The CPU upgrade was so easy.
If I do sell them, whoever buys them will get absolutely perfectly looked after computers. I'm very obsessive about avoiding scratches, marks or any other blemishes on my computers. I've seen some for sale with dings, deep scratches, bent feet and I wonder what the hell the previous owner was doing - it's an expensive bit of equipment, for goodness sake take care of it.