What FPS will I get in ULTRAKILL at 1440p?

At 1440p Ultra native, expect around 180 FPS. With DLSS Quality you can push higher.

Does GeForce RTX 5090 AORUS STEALTH ICE support DLSS or FSR in ULTRAKILL?

Yes — ULTRAKILL supports dlss2.

Yes — the GeForce RTX 5090 AORUS STEALTH ICE runs ULTRAKILL at approximately 240 FPS at 1080p Ultra (native, no upscaling).

✓Yes — Excellent

Expected: 240 FPS @ 1080p Ultra (native). This GeForce RTX 5090 AORUS STEALTH ICE is currently $3999.99 at Newegg ↗