A couple of things come to mind,
First the 18 core CPU with hyperthreading is probably overkill, but it won't hurt anything except the price.
64 Gig of Ram is probably overkill as well, unless this is your primary video editor and you are using Adobe editing software, then the sky is the limit or money is.

Second you may want to upgrade to a 1000 watt or 1200 watt power supply the RTX-2080 TI is quite a power Hog.

Third if you use any Black Magic capture card(s) add at least one case fan that blows directly on the card(s), they get HOT even when they are not being used. Also another case fan to move the hot air out. Notice that the Yuan 560 card does not even have a fan, they run much cooler.

You may want to consider the Yuan 4K SDI capture card, they now have a four input 12G 4K card, Here is the link: https://www.yuan.com.tw/...e/4k/sc710n4_12g_sdi.htm
That 12G card probably gets hot as well the SC-710 N4 HDMI version does.

Have fun building it!
Steve

Pretty much ditto to most of what Stream Breeze said with a few revisions, critiques, and addendums.

For vMix anything more than a 9900k with 16g of ram and a RTX2060 is just massive overkill. That said it all depends on your use case scenario. Ultimately you need alot of IPC which you can get with most modern processors assuming they clock up to 4.2GHz or higher. On CPU Cache does help but only so much.

If you built any highend system with a 212 EVO i would have to cry. 212 is great for lower powered systems but once you pass 6 cores you really need something beefier like a Noctua U12, D14, or d15..not to mention a few others from other brands i wouldn't mind mentioning...but the Noctuas are generally quiter for the performance level.

Look for a case that is airflow centric not flashy or cool. Be sure to load it with the ugliest Noctua fans you can find and make sure to keep your case pressure possitive so that your filtration works correctly for your case. This means more fans sucking air into the case then blowing out. For all the hardware you previously mentioned i would never do an airflow case and would go with a liquid cooled system so that the components didn't have a chance to bake while the fans tried to pull the head away from those beastly parts. BTW if you go with Higher End system specs go with much larger cases if you plan to Air cool. You will need around 6 fans pushing in alone to keep up with the air cycling you will need if you push the components anywhere close to their max performance. Oh and 850watt power supply is fine for that system although 900watts would put you closer to the efficiency curve. You never want to push power supplies past 80% of it's rated performance as it will use much more power than you will get out of it. That said there is nothing stopping you from running a 750watt PS with that system and ever having any issues, assuming it's a quality Power supply.

As far as capture cards are concerned i think you are on the right track.

Chad