Is the Tempest GP27U good for PS5 and Xbox Series X?

Yes. It accepts 4K over HDMI and supports high refresh rates, so consoles can run at their top modes. Check that your console's HDMI cable and settings are set for 4K output.

Does it have USB-C for a laptop?

Yes, it includes USB-C along with HDMI and DisplayPort. That lets you connect a laptop for video and use the monitor's USB hub.

How does mini-LED compare with OLED here?

Mini-LED gives higher peak brightness and no burn-in risk, but OLED has per-pixel blacks with no blooming. The GP27U is the better pick for bright rooms and mixed work.

Can I turn off local dimming?

Yes, local dimming can be disabled in the menu. Turning it off removes blooming but lowers contrast in dark scenes.

Is 27 inches too small for 4K?

It gives very sharp text and detail, but you will likely want display scaling in Windows or macOS. Gamers often prefer this size for a single-screen desk setup.