I have a similar sized but carpeted room. To make the room play bigger I always keep the room door open. I also had a closet in this bedroom, I removed the closet doors and got about 4 feet of more depth. Now that can cause other sonic issues, so I have some acoustic absorption panels in the closet. I worked with GIK Acoustics to fix other sound issues with acoustic panels. Cost me $700 for the ugly panels.
I have a floor stander speaker in this small room, and I think I am getting about 90% of the best abilities on the speaker. Still not good as a big room but the sound is fatigue free and rather good. My virtual system of the ’Office’ has some photos.
Office System | Virtual Listening Room (audiogon.com)
You could also work in some DSP using someone like
to put any sized speaker into your room. I used Convolution files (DSP), loaded into ROON Core, that was created by Accurate Sound. That worked great. However, I was able to physically remove reflections by adding an additional acoustic panel and also moving some things away from the speakers. The taming of these reflections made me realize I no longer needed the DSP. Not everyone can do that, so DSP is a good choice to tame a room.