If you wanna a simple solution, get an HDMI pass through with an audio splitter. This way, you will guarantee both video and audio signals come from the same HDMI output port from the TV Box. If you are still on 1080P resolution, perhaps this FHD 1080P Converter Adapter 3.5mm Audio Output Jack is what you want. For 4K video, perhaps this [HDMI Audio Extractor AY78 HDMI to HDMI Optical TOSLINK SPDIF + 3.5mm Stereo Extractor]. For a 4K video, perhaps this (https://www.aliexpress.com/item/Hot-HDMI-Audio-Extractor-AY78-HDMI-to-HDMI-Optical-TOSLINK-SPDIF-3-5mm-Stereo-Extractor-Converter/32830875128.html) is what you will need. Just one word of caution, product like this may not be stable and will cease to function after a few months of usage, particularly if it heats up while in use.