As a Tacx owner, and a background in science (where measurement matters), this is one of the silliest threads I’ve ever seen.
The real answer is none of them are technically correct and the answer that makes the most sense is to use the power measurement you use outside for inside (ie: the crank or pedals).
As for eSports, you’re not after “correct power”, just the one that inflates your numbers the most. That will likely be some kind of single leg crank arm meter only. If you have to use the trainer, find the one that reads highest. If you’re really a baller, you buy 5 of the same “highest model/ brand” at a time and test all to see which of them reads even the highest. People do this with engines in stock / spec classes all the time, spending tens of thousands of dollars and keeping the one that only makes 1-3hp more.