Need Advice on Reflections

There are several techniques (and hacks) and I'm confused.

That's probably the place to start.

Most games today use game engines that do the work for you.

If you are doing the rendering, what of the many approaches are you doing? Where are you doing it, the CPU or shaders? What have you already tried and what didn't work about it? If you haven't tried anything yet, why not?

The approach the modern engines take is adaptive ray tracing done in shaders. It handles everything, including reflections. The texture of the material is typically a mix of geometry, shader-driven adjustments to the material position, and surface normal adjustments done both by a texture and often also by shader. The approach is usually far beyond what an individual hobbyists could do, most individuals would probably implement it with either cpu-based ray tracing or a shader doing screen-space reflection.

Looks like unshadowed area lights to me. Usually done by integrating form factor of shapes like rectangles, spheres, or polygons.
It's not very expensive. Due to the lack of shadows no ray tracing is needed.

Some random article, but there is a lot more to find: https://learnopengl.com/Guest-Articles/2022/Area-Lights