What's a Good Starting Point For Me?

Hi,

I have never built a PC before. That said, I'm not new to computers and I've fixed, upgraded, and rebuilt many computers, just all laptops (including quite a few Macs) and a few Intel NUCs.

I want to upgrade my current desktop setup if I can, I just have a very small budget.

Currently, I'm running an Intel NUC 8, with an 8th gen quad-core i7-8259U, Iris Plus 655 graphics, and 16 Gb of DDR4. The performance is fine. This is with an (actually pretty nice) 27" 1080p 75Hz IPS monitor, and a good mech keyboard and an MX Master 3S.

I'd like to upgrade the monitor to about QHD or UHD @ 120Hz, and I don't really need even need 120Hz, it just looks nice.

I'm at college still for the next two years, and I have very limited desk space and can't put a PC on the floor, hence the very cute and tiny NUC.
A small and quiet PC would be most ideal. I'd give significant performance for that.
I really like the idea of an ITX build, but it just gets so much more expensive.

For a use case as a desktop, it would serve as the kind of everything pc. General web browsing and school, Youtube, movies, etc. Along with CAD modeling and simulations in Solidworks and fusion, possibly apps like Illustrator and blender. Some random Windows-only programs like Multisim.

Gaming. Not often, and nothing competitive. It would be some smaller games like Portal, but mostly Minecraft at 60+FPS with shaders cranked, if it can manage it.

For performance, I'm looking to at least match the performance of the Windows laptop I've been using for all this. A 17" Dell Precision 5770 with an i7-12700H, 32Gb DDR5, and an Nvidia RTX A2000 8Gb GPU.
That laptop is great, I'm just really enjoying the convenience of a desktop, and it's not very quiet at 100%.

I'd also really like to be able to upgrade it later, so nothing super old.

My actual question. What should I be looking at as far as specs, and what's the best way to achieve this on a budget (like <$600)? I'm very not against used parts or old prebuilts, that was my expectation.
And based on my research, an Intel i5-12600 and RTX 2060 is about my minimum for performance.
Is this realistic, and what's a good place to start if so? I want it as small as possible. Thoughts?

I'd buy an M4 Mac Mini, but I do actually need Windows.

Thanks! And I apologize for any ignorance here