Right, dash requires a full action, so you cannot attack if you travel above your max movement in one turn. You can use whatever mental gymnastics you need to in order to justify RTwP being truer to PnP over TB - but there's literally a mechanic called turn order soooo. I'm all for the people that say they prefer RTwP games over TB. When you start saying that RTwP is better at translating the PnP experience, however, you're just flat out wrong. I'm not bashful about admitting I'm more of a fan of PnP over crpgs. I play crpgs because I like the underlying rpg system (DnD core rules) and every time I replay one I have a constant dull pain over the RTwP implementation. That's just my cup of tea tho, I'm not debating the merits of either system.
Well, I actually suggested that something other than TB or RTwP might work better, somewhat as a devil's advocate. My personal preference for combat is RT control over one character with mechanisms in place to influence the others through pre-set instructions ( like DA:O ) or maybe shouted orders of some kind. Both RTwP and TB break the flow and require me to control the other characters, which I prefer not to do.
What works best depends on what Larian are trying to do. If the intent is to provide a PnP 5e multiplayer simulator with BG3 as a game module, then you would follow the 5e rules and definitely implement it as TB, possibly requiring a DM seat to play.
However, if the intent is primarily to provide an RPG video game that is based on the 5e rules, then their decisions are less clear cut. It depends more obviously on their "vision" for the game than what the rules themselves actually say. I don't remember any computer-based D&D title that actually implemented the PnP rules correctly and completely; some were always modified or dropped, either because they made no sense in a video game context, or because they were impractical to implement.
As @Hawke points out in another post, creating video games is nowhere near as easy as many gamers think. I used to like PnP because of the feeling of being able to explore and interact, at will, with a completely different world, where combat was just one occasional activity. That has not really been possible in computer games yet, because building all the world-evolution systems that would be needed is beyond what is practical in a discrete game. So my best hope is for a well-written, well-paced story with multiple ways to advance; but my fear is that it will just be a series of fetch-and-carry quests inerspersed with unavoidable combat.