I have both a Samsung 40" MU7000 2017 & Samsung 55" Series 8 2019.
Series 8 bluetooth find, pair, and connect work superb.
However, the MU7000 does not.
It will find my headphones, and ask to connect, but the pairing fails each and every time. I did pair the headphones about 6 months ago, and the pairing disconnected on its own only about 15 minutes into using the brand new head device.
Like I said, the series 8 TV bluetooth works as advertised.
Something is amiss in the MU7000.
Have you tried unplugging the unit for about 2 minutes and retrying directly into a wall socket? Please ensure that you have the unit updated fully with the latest firmware. Try resetting your network and Bluetooth settings next. Last but not least, if this doesn't work a factory reset may be in order.