Ahh, most of the cost is CPU. It’s so expensive to have register memory, that you have l1 l2 caches. Each further away and cheaper. RAM is the cheapest which is why you can have so much of it. Try having 16G of register memory.
UMA is a step towards that, but not quite.
Look at a Dell or HP server configurator website to see why.
If you "only" need GPU, a craigslist search should find a less expensive 2 or 3yo server to plug your latest GPU into.