FWIW jasonbourne71 makes a much- overlooked observation, that is the importance of the location of the listening position can greatly affect the sound you hear from your speakers (although I disagree with his suggestions for speaker placement).
The absence of bass information can direct your attention to the higher frequencies and making them sound brighter than they would if your bass FR were neutral or slightly boosted.
Your listening position could be in a bass null and moving it forward or backward could possibly solve both of your audio problems if you put it in in a neutral zone or a small node. Ditto for moving your speakers out further from the wall than you presently have them. You might just find a bass node to solve you bass issue and actually improve your treble response and bass clarity.
I know zip about your electronics beyond a perception that I gained from reviews that they might be, sound wise, less than ’warm’ and exacerbate problems when connected to speakers which might also be less than ’warm’. IME brightness can often occur from this syndrome as manufacturers are focused on maximizing imaging potential by over emphasizing the mids thru high frequencies. Folks caught up in this tend to buy separate components with similar design goals and end up with a bright system.
FWIW, if your room dimensions as listed mean you have a 6 1/2ft ceiling this might in and of itself create problems. I’ve never heard a room with so low a ceiling, but I could imagine that it would give you some increase in first reflections and tilt up your highs. I have no ready solutions suggestions for that.
FWIW, using an equalizer as a tool if not a permanent component might be helpful to find the frequencies which need to be changed to get you where you want to go, sonically speaking.