REW software, a UMIK microphone, and time to learn about acoustics and measuring.
Rooms are so different, as are preferences, that until you really know what you want to change and why, suggestions about products just creates a needle-in-a-haystack problem for you.
Once you spend some time learning (including critical listening) what you can do with what you have (speaker position, listening position, objects already in your space), you can then move on to what needs to be adjusted -- and which product types will do that.
Rooms are so different, as are preferences, that until you really know what you want to change and why, suggestions about products just creates a needle-in-a-haystack problem for you.
Once you spend some time learning (including critical listening) what you can do with what you have (speaker position, listening position, objects already in your space), you can then move on to what needs to be adjusted -- and which product types will do that.