Which model turntable are you looking at or what is your turntable budget?
Turntable with a built in or external phono preamp > RCA Analog to Digital Optical Toslink Coaxial Audio Converter > digital optical input on the soundbar.
Or try Bluetooth.
The slight delay doesn't bother me the few times I have played a turntable with Bluetooth to a speaker setup with Bluetooth input.
It may only bother people who are sitting rather close to the turntable playing at a low volume with the dust cover open and can hear the faint needle talk/chatter and the delayed audio over Bluetooth through their speakers.
As long as you are not sitting very close to the turntable, the volume is louder than the faint needle chatter, or you have the dust cover closed then Bluetooth may be fine.
A later upgrade from the soundbar would be an AV receiver and passive speakers, scroll down past the turntables and starter powered speakers, for both the turntable and TV.
Analog to optical converters do exist but they’re less common than the other way round
You'll have better luck with optical. Get something like this but make sure your RCA cable is running most of the length of your connection to the speaker, as optical toslink cables tend to break easily under repeated movement.