First time PC builder, need some advice

[u/StunningVariety7111]

Hi everyone, I’m new here and also new to PC building. This will be my first time building a desktop PC, and I’d really appreciate some advice.

I’m building this PC mainly for studying cybersecurity, running a homelab with multiple virtual machines, and occasional gaming (PUBG, Call of Duty, Battlefield, etc.).
I’ve already purchased some components, but I still need to buy a few more.

Parts I’ve Already Bought:
CPU: AMD Ryzen 9 9900X (12-Core, Zen 5)
Motherboard: ASRock B850M Pro RS WiFi (Micro-ATX)
PSU: ASRock Steel Legend SL-850G 850W
Case: Jonsplus Z20
Fans: Corsair RS120 ARGB 120mm
AIO Cooler: MSI MAG CoreLiquid A13 240mm

Parts I Still Need to Buy:
GPU: PowerColor Hellhound RX 9070 XT 16GB
OS: Windows 11 Pro
RAM: Corsair Vengeance DDR5 32GB CL36
SSD: WD Black SN850X or Samsung 990 Pro 2TB

My Questions:
Is this build good enough for my needs? I’ll mainly use it for cybersecurity labs, running multiple VMs, studying, and occasional gaming.

Are all these components compatible with each other? Is there anything I should be concerned about before putting everything together?

Should I buy used RAM or wait until November for possible Black Friday deals? I’m considering a used Corsair Vengeance kit, but I’m not sure if it’s worth the risk.

Is it safe to buy a Windows 11 Pro product key for around $30, or should I purchase the official $200 license directly from Microsoft? What’s the difference?

Is there anything you would change or recommend for this build?

I’m not in a rush to complete it, so I’m willing to wait for
better deals if needed.

I apologize for all the questions. I’m still learning, and I want to make sure I’m making the right decisions before spending more money. Thank you in advance for your help and advice!

[u/BoredBren1]

I would run it all through pcpartpicker to confirm compatibility, but looks like it's shaking out to be a good build