To put in context,the 8C salvage of desktop Cometlake is still efficient enough to be found in HEDT replacement laptops - 10C isn't(they are all the same chip). If you look at various threads on Google,you have to choose the motherboards and coolers very carefully to avoid issues with the Core i9 CPUs,as they literally overclock themselves out of the box. The Core i9 10850K is a little
less extreme in that regard than the Core i9 10900K but the bin quality is more variable.
AT reviewed it:
https://www.anandtech.com/show/16341/intel-core-i9-10850k-review-the-real-intel-flagship/24
Some reviews show it having less power consumptioon than a Core i9 10900K,so you need to be wary in case you get a poor bin. Even the best air coolers(Anandtech used a top end Noctua on an open air testbench) just about managed.
Plus if you can't wait the 8C variants will have less issues in terms of power consumption,and cooling. It will still be a huge upgrade over what you have.
However,Rocketlake is out next month on March 15th:
https://hexus.net/tech/news/cpu/147437-intel-rocket-lake-hard-launch-tipped-monday-15th-march/
It will also bring PCI-E 4.0 to the Intel platform,which means feature parity with AMD. As it does look like you keep platforms for a longtime,it will not only be useful for future GPUs but also for storage. Almost the entirety of NVME SSDs will probably be PCI-E 4.0 in a few years time.
Also remember,Cometlake isn't going to disappear off the face of the earth in 3~4 weeks. But unlike many here,I am much more patient and have been upto 7 years on my previous platforms to AM4.
DDR5 is going to be quite expensive IMHO,ie,a bit like DDR3 was for your X58 platform when socket 1366 was first released. Even if Alderlake is decent,that DDR5 cost is going to be the problem here.
It's a shame you don't have a recent dGPU,as the Ryzen 9 3900 and Ryzen 7 5800X bundle deals do make them reasonably cheaper than normal.