Flashy lights appear unintended i think it maybe volumetrics or bloom

You can adjust the intensity of the bloom by going over its setting in the render properties (camera icon).

I say around .3 or .4ish

Here’s the final render. I added irradiance volume outside the room so that all the objects inside can reflect and bounce lights from three light sources: spotlight, emitted plane (near the walls), and light materials on the cube.