There are a couple of sets on Amazon namely Avantree branded. They are all bluetooth apart from the the last which is RF.
Avantree Opera (EQ Voice clarity)
Avantree Ensemble
Avantree HT5009 (voice clarity)
Avantree HT280 – more akin to the Sennheiser RS120
They all say they Low latency below 40ms apart from the HT280 which I can’t say Ive seen mentoned. They won’t be on the the same level as Sennheiser with sound clarity. I cannot recommend or not recommend them soley because I know nothing really about the brand so comment on sound quality or lngetivity. However they have a decent star ratings above 4. I advise you to read the reviews and comeback with any questions I will see if I can help. They come with 2 yrs guarantee I believe.
There are advantages and disadvantages of bluetooth. One of the advantages is you could connect them to other devices where as the Sennheiser are purely for TV.
The Opera set having EQ voice clarity so may be the wiser buy but they are £129. There is also a 30day free trial, allowing you to decide and see if there are any latency issues.
I think if it was me I’d opt for the used Sennheiser 175’s for the price alone listed at, in my previous comment purely because I know they are premium in this area and would have no issues with there intented use, but they are soley for TV watching. However you are the one that has got to decide and I do recommend at least looking at the reviews of the Avantree.
I will look at other options later – any questions in the meantime do ask.