I dont think the speakers are the issue.

On wall speakers need proper placement and are dependant upon loading them against a boundary as Mojo has mentioned.

Your room doesnt appear to allow proper setup as your picture shows. I would highly recommend drawing out your room on a piece of paper and google ITU Multichannel setup.

Think about turning your room to best fit the template.

If your room is not capable of a standard setup in terms of placement it is likely best to choose another room.

https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BS.2159-8-2019-PDF-E.pdf

People trend towards on walls or in walls assuming they can make a tricky layout more flexible. That is not the case.