Room is way too bright.

Thanks to all for your many suggestions and comments. 
And yes, I should have done a bit more research before asking about reflection points. My apologies. 

Finding the First Point of Reflection 
 

https://youtu.be/fs_0hnD_JNQ?si=dS8IqX8E2zCYmh00

I have 17 windows in my large listening room. Using Marigo tuning dots made huge positive difference with no downside. Visually my wife initially did not like but got used to the look after a week or so.

https://marigoaudio.com/zw-window-resonance-damping-discs/

You should consider BACCH4MAC.... their room correction software (ORC) is amazing.... I have an office with windows along both sides and it fixed everything as well as made the speakers completely disappear...  most incredible technology I have ever heard 

Theoretica Applied Physics BACCH4Mac Stereo Purifier Review - The Absolute Sound

Here is a small trick that can help you in this journey. Stand or sit in the listening position and clap your hands loudly once. Listen for the effect. If you get a jittery echo as the sound fades away that is a problem. It is called "slap echo." Now walk around your room and do the hand clap and listen. Get a sense for how the decay is different at different locations. Your master bath is a good place to hear the extreme situation of a very live space with poor acoustics.

Now do that in several other rooms in your house. Listen for the quality of the decay. Does the decay happen quickly or do you hear a slap echo during a longer decay. Take some time and get a sense of the acoustics of your rooms and their properties.

For your listening room the quality of the decay is the critical factor you will be managing. You want a clean decay without slap echo that is fairly short. Try hanging some double or triple folded blankets on your windows and the walls in various places. As you add material do the slap test to hear the effect on your room's acoustics. Now you are ready to listen to music. Find out what your system sounds like in a deader (is that a word?) space.

I strongly urge you to work on room acoustics before you try EQ, cables, or room correction. You cannot cure poor room acoustics with any of these things. Once you get a good idea of how much sound absorption you need you can work with your significant other to figure out the decorating/absorption compromise. There are a bunch of companies that make this stuff including acoustic curtains and there are many solutions available that can look nice.

If this is your main living area you will also gain the benefit from better acoustics in everyday activities such as watching TV and especially, converation with several people in the room. It is easier to understand what people are saying if the echo is controlled.

Hope this helps.