I have a slimline modern Panasonic tv and always have subtitles turned on as the volume is not always loud enough especially on films and many of the Sky channels like PBS which do not allow subtitles. I miss huge amounts of dialogue especially when watching films. I need to buy a sound bar but only to increase the volume for speech. I never listen to music and do not want to unnecessarily buy one with all bells and whistles. Do I need one with Bluetooth - I don't even know what that is? I am 76 and not even deaf athough my kids say I have the tv on too loud.
However if you're the only person watching the TV, and if your set has got a 3.5mm headphone socket, you might like to consider using wireless headphones. Jennyjoan (who is hearing impaired) uses these, as do other ABers with good hearing (including Woodelf and myself):
https://www.argos.co.uk/product/2473666