I was going to post that you probably need to adjust the audio on your telly. (9 out of 10 people never seem to bother going into the audio settings to optimise them for the room that the TV set is and and for their own listening preferences). However, having just checked out the relevant section of the programme on BBC iPlayer
(
https://www.bbc.co.uk/iplayer/episode/m001fgqr/bbc-young-musician-2022-7-jazz-final )
I find myself agreeing with you that the sound balance isn't that good.
(It should be noted though that I was using my laptop, rather than a telly, where higher frequencies tend to predominate in audio output. It's possible that the audio settings on your telly are configured similarly, as would happen, for example, if you've selected a 'Speech' setting within its audio preferences, instead of a 'Music' one)