Bluetooth Transmitter (APT-X) for Two: Dual Link Avantree, Two Single TaoTronic BA08 (using 3.5mm Audio Splitter) or Other?

Hi legends,

I've researched this, read the other forum posts etc but haven't found the answer to this specific scenario discussed.

My wife and I want to be able to watch tv with no lag using our bluetooth aptX headphones. The audio is via a sound system, 3.5mm audio jack.

I've researched Bluetooth transmitters that support dual link aptx, and listed two Avantree models which I think accomplish the task. We both have VAVA MOOV 28 headphones, they're aptX, aren't "True Wireless", so they seem to clear all the hurdles for dual link aptX transmitters. Beyond your thoughts on that, I've got two challenges at the bottom I'd love to hear from you on.

Candidates:
* I like the reviews on the Avantree PRIVA 3 TV Dual Link aptX Low Latency Wireless Stereo Transmitter ($88 delivered Amazon AU).
* Even cheaper is the 2018 Avantree Audikast TC418 ($69 delivered Amazon AU)

Challenges:
(1) What's the real difference between Avantree's Priva 3 and the 2018 Audikast (TC418)? The latter has slightly higher average score (4.5 vs 4.4), and support for optical digital. Avantree's own website lists it as $10USD more expensive, yet on Amazon AU it's almost $20AUD cheaper. In short, for my scenario can anybody suggest why the 2018 Audikast (TC418) isn't simply a better buy?
(2) For around the same price I could just get two TaoTronics TT-BA08 transmitters ($36.99 ea delivered Amazon AU), and connect them both to the stereo jack using a 3.5mm audio splitter. If so, this would also give us the flexibility of an aptX transmitter each for work/personal when we're not watching tv. NB: according to Amazon, the TT-BA08 does not support aptX in dual link. It does either, not both.

Thanks for your input!