It's not bad choice for me, I would rather 9800X then i9-9900K.
I more believe in HEDT platforms and I'm ready to sacrifice few fps and little single threaded performance only if I have chance to buy stronger model later no matter on decision later. Special because I don't like to new chipset show up after 10-12 months.
Someone to give me to choose I would rather stayed on X99 with i7-6900K or i7-6950X, then any combination of Z390.
Yeah I'll just stick to my 9980XE and X299 Asus Omega board for now but thanks lol. I just don't see the use in X299/HEDT unless you're going to go all out with cores. Buying the 3950X though, should be a laugh on chiller daily.