What FPS will I get in Arma 3 at 1440p?

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

Does GeForce RTX 5080 GAMING SOLID support DLSS or FSR in Arma 3?

Arma 3 does not currently support upscalers.

Yes — the GeForce RTX 5080 GAMING SOLID runs Arma 3 at approximately 240 FPS at 1080p Ultra (native, no upscaling).

✓Yes — Excellent

Expected: 240 FPS @ 1080p Ultra (native). This GeForce RTX 5080 GAMING SOLID is currently $1899.00 at Newegg ↗