Phonak offers a TV connector - as is common in the world of hearing aids the specifications that a normal user can find on-line aren’t very complete. The Phonak device has “low latency transmission from the TV to the hearing aids” whatever that actually means. See:
TV connector Technical Data
The taotronics device you mention claims low latency for aptX - you would need to find out if your hearing aids work with that codec as it is not standard codec required by Bluetooth specifications. Again, a real specification of the latency would be useful as compared to “low”.
I have no experience with Phonak or their TV connector. I have a similar Oticon device for my Oticon OPN S 1 aids. The technical data sheet from Oticon specifies the latency from the input of the TV connector to the output of the hearing aid speaker and it depends on the input (analog or optical) and the encoding of the optical signal. For a normal optical input (PCM) the latency is 28 msec and for Dolby digital it is 45 msec. For analog it is 25 msec. The Oticon TV adapter has an optical output - it appears that the Phonak device does not so you would need an optical splitter. I expect a powered one would provide a more reliable connection as the non-powered ones split the optical signal and that may attenuate it enough to cause issues with one or both of the devices connected to the split outputs.
The User Guide for the Phonak TV connector does cover what optical input signals are allowed. It appears that the only optical format allowed is Stereo (PCM) - Dolby or DTS are specifically called out as “wrong”. So if your sound bar needs other than standard PCM, then the Phonak device may not be correct for you or you would need to use the analog (line level) output from your TV as input to the TV connector.
As d_Wooluf says, some users are bothered by latency. In my case, I mute my hearing aid microphones and listen only to the streamed sounds as that is better for me. If I don’t mute them and the sound bar is on, the small latency difference smears the sound and makes it harder for me to understand voices. Muting the microphones also cuts down on the room noise sources like the fan for AC/heater, again improving my understanding of voices.