[Hardware Build] 1x RTX 5090 (32GB) + 9950X3D for Headless Rental Node. Air Cooling w/ A/C. Feasible?

Hi everyone. I've been lurking here for a while and finally decided to build a dedicated AI server to rent out on RunPod or Vast.ai.

The Context:

* Cooling: I will install a dedicated 24/7 Air Conditioner set to 18°C (64°F) directly blowing at the server.

* Constraint: Since it's unattended, I am terrified of AIO liquid cooling leaks. I want to stick with Air Cooling for maximum reliability.

The Proposed Build:

* GPU: 1x ZOTAC RTX 5090 32GB (Planning to add a 2nd one later).

* CPU: AMD Ryzen 9 9950X3D (Will run in Eco Mode 105W to keep temps low).

* Cooler: Noctua NH-D15 G2 (The best air cooler available).

* RAM: 96GB (2x 48GB) DDR5-5600 SK Hynix (Consumer RAM, aiming for stability over speed).

* Mobo: ASUS ProArt X870E-CREATOR WIFI (Need 10G LAN and bifurcation support for future expansion).

* PSU: Seasonic PRIME TX-2200 (Overkill, but preparing for dual 5090s).

* OS: Ubuntu Server 22.04 LTS.

My Questions:

* Thermal Reality: With a dedicated A/C in the room, can the Noctua D15 G2 handle the 5090 + 9950X3D under 24/7 load? Or is a blower-style card mandatory?

* RAM Stability: Is 96GB (2x48GB) on AM5 stable enough for Linux/AI workloads? I heard mixed reviews about high-density DDR5 on Ryzen.

* Rental Demand: Is a single RTX 5090 (32GB VRAM) attractive on RunPod/Vast? Or should I have looked at used A6000s (48GB) instead? (Though 5090 is much faster).

The budget is $6800.

Any advice would be greatly appreciated. Thanks!