I think it’s worth saying that half of your battle might be in your texture selection too. A lot of those materials feel a little bright/over saturated and not to realistic themselves. A lot of what made Koola’s work great was his texture selection, color pallet and the LUT he created for color correcting.
Also, it can be very helpful if your trying to come to grips with your lighting. To replace the materials in your scene with a basic “clay render” material. Just a nice medium grey. Work out your light bounces, start working the resolution of your lightmaps up as needed. You’ll be able to bake a little quicker and most importantly you can judge the color bounce and light map quality alone. Then start adding your materials slowly one by one. It easier to get a few materials to work well together color wise than it is to have to go back and re-tweak the entire scene.