MacOS 26 bluetooth sounds thin

I listen to music on a Vifa Reykjavik bluetooth speaker.

Until now I have used a 2015 MacBook Pro with MacOS 12.7 Monterey and a 6th generation iPad.

I have recently bought a Mac Mini M4 Pro with MacOS 26.

If I play something on the Mini, the sound is thinner. It doesn't matter what I listen to, Tidal or YouTube, the sound is generally thinner on the Vifa Reykjavik.

However, the sound from my MacBook Pro or my iPad (via bluetooth) is nice, sounds fuller and warmer. I can listen to it for hours, however, the sound from the Mini is hard to listen to for long periods as it sounds thin, not very musical, artificial.

It sounds like the music from the Mini is lossy as the music is thinner, not so lifelike, artificial... like mp3 vs CD.

Anyone experienced anything similar? Is it the Mini? Is it MacOs 26? The speaker is the same, however, the sound differs, depending on the machine (or OS?)

I have downloaded an EQ app to the Mini, however, it does not solve the issue as the sound is still thin and not very musical.