The best most sure-fire approach will be to buy one 2x3 ft 1" thick panel of Owens Corning acoustic panel. Light, inexpensive, highly absorptive and super easy to move around. You probably won't want a full panel in the end but a full panel will make the difference real obvious and easy to hear.
It looks to me like that one window is pointed straight at you. Try the panel there first. But try it lots of other places too. Think of it as mapping out the rooms sound patterns. Then when you know for sure where the problem reflections are coming from the next step will be to find out how little material you can get away with and where to put it.
OC cuts real easy with a razor blade. Most professional panels are OC with nothing more than a frame and fabric. You might try cutting it down and wrapping with some nice fabric. If you do this keep in mind that if the fabric is too heavy and tight weave it will nullify a lot of the absorption. Fabric like speaker cover material works better.
Or even if you don't use the panel for that it will still help you figure out if the blinds you're considering will work or not. OC is a lot cheaper than blinds!
Finally, after solving your immediate problem you might consider testing how it works in the corners. This was how my room looked 15 years ago with some OC panels on the walls for testing and some others cut and covered with fabric up in the corners.
https://www.theanalogdept.com/c_miller.htm
It looks to me like that one window is pointed straight at you. Try the panel there first. But try it lots of other places too. Think of it as mapping out the rooms sound patterns. Then when you know for sure where the problem reflections are coming from the next step will be to find out how little material you can get away with and where to put it.
OC cuts real easy with a razor blade. Most professional panels are OC with nothing more than a frame and fabric. You might try cutting it down and wrapping with some nice fabric. If you do this keep in mind that if the fabric is too heavy and tight weave it will nullify a lot of the absorption. Fabric like speaker cover material works better.
Or even if you don't use the panel for that it will still help you figure out if the blinds you're considering will work or not. OC is a lot cheaper than blinds!
Finally, after solving your immediate problem you might consider testing how it works in the corners. This was how my room looked 15 years ago with some OC panels on the walls for testing and some others cut and covered with fabric up in the corners.
https://www.theanalogdept.com/c_miller.htm