It used to be much worse. Now I have 17 wool absorbers (6 glass wool 120x60x20cm, 6 stone wool 100x50x10cm, 5 stone wool 120x60x10cm) and a bass trap.You have a very lively room.
Nothing more I can do about it. Either accept it or change the apartment which I like
@ernestcarl I still have not received any response from Lyngdorf support regarding phase, but I found this video on yt where mr. Roland Hoffmann says a few words on the subject