Advice New to small PCs

[IkeaGnome]

After finally getting tired of my "impulse" built large pc I'm wanting to downsize. A lot. I'm tired of RGB blinding me while I try to play games, not being able to manage cables on my desk well because some are stretched just because of how far away my massive tower has to be. Currently I have a i9 and 2070 built. I want to get into a small, non flashy case. Mostly playing games but occasional light editing. I'm wanting to step down to the i5-10600k for it's performance in games. I think I have a decent parts list put together, but would like opinions. With me already having a built pc I can really take my time with this one and do fun stuff to it. I want to get into sleeving cables and possibly watercooling with this build. I do want to reuse my current video card. I didn't pick any memory because my m.2s can come over to the motherboard I picked. I went with that one because I have had really good luck with ROG parts. I'd like to keep 32 gigs of ram. Usually when I play games, I have Spotify, Discord, and a few other things going on in the background. Just in games I don't get close to using 32 gigs of ram, but I tend to get close enough that I'd like to stick with it. I didn't pick a CPU cooler or fans yet. I want to go with Noctua. From what I've seen there is some modding that happens to make a watercooling set up fit in the A1, and it seems like those are with smaller GPUs. I'm curious on the possibility of this with a larger GPU. I'm not against cutting and modifying this case to make it work better for my needs if I have to. I already want to pull it apart and give it some paint in a different color. I wasn't able to pick the GPU I currently have on PCPP. It is the ROG STRIX 2070, triple fan.
Is there anything major I'm missing? Any big reasons not to do this?

https://pcpartpicker.com/list/CQgrk6

 

[spiral]

I guess your i9 is a 9900 variant ? if so there is no reason to change it for a 10600 you will just lose too much money going to z490 for no gain.(unless it's impossible to get a z390 itx board)
The Coolermaster NR200 looks interesting since it has a ventilated side panel instead of a window. I have a TU150 with a Strix 2070S and i had to raise it from the desk on some makeshift feets to reduce the noise from the gpu. It still works stock, but reducing the fan rpm on the gpu made it more livable for me.

 

[tinyitx]

I concur with @spiral on the choice of CM NR200, over the InWin A1 Plus. One main feature of A1 Plus is the 'transparent' base which is RGB addressable. Since you are tired of RGB, avoid the A1. Also, A1 is 21.8L (vs NR200's 18.2L). Thirdly, NR200 offers more watercooling support than the A1.

 

[IkeaGnome]

I like that NR200 a lot. Keeping my i9 wouldn't be too hurtful in an ITX? That was my main reason for thinking 10600. Right now I have a ton of fans working to keep it cool and was worried smaller case, less fans more heat if that makes sense.

 

[ParallaxStax]

The CM NR200 can fit cpu coolers up to 155mm tall and up to 280mm radiators. If you want to go air cooling, I would choose the Scythe Mugen 5 or for liquid cooling the Kraken X63 or Corsair H100.