Except pcie 4 is a big fat meh. Maybe in a few years it'll matter at which point mobos will be way cheaper, but right now nothing can use it except nvme drives doing large file transfers. If I cared much about that I could nvme raid on existing x399 for way cheaper than a new pcie4 mobo anyway.Issue is that, even though they promise backward compatibility, existing TR mobos don't support PCIe 4, whereas TR3 should support PCIe 4 with the new boards that come out. So you're potentially looking at basically a full platform update.
Also, as for TR1 deals... https://hardforum.com/threads/amd-tr4-1920x-249-and-1950x.1982139/