As to what a difference between 6sec RTwP and IgoUgo Turn-based - those are different rulesets - the difference should be self explanatory.
Yeah, I agree. His claim was that RTwP is the better choice because it can also be TB by only using an auto pauses after every 'round', which may be true with a certain kind of TB. However, doing so will not produce the kind of turn based combat Larian used in DOS and has shown to be in BG3, as really should be clear to anyone posting here.
the kind of turn based Larian used in DOS isn't D&D. 6 second rounds is D&D. You can look it up in the PHB.
D&D combat is an abstraction of real time combat that uses rounds to facilitate multiple people sitting at a table, not a single player video game, which is one of the reasons WHY RTwP was chosen for BG.