Checking with your inspector is always good advice.
I am surprised that “they” are trying to get away from using metal conduit as a ground. Studies have shown properly sized and installed metal conduit systems are superior to aluminum or copper conductors for clearing a fault.
https://steeltubeinstitute.org/wp-co...ing_042820.pdf is one such study.
True, the conduit may have lower resistance than a ground wire just by virtue of the much higher cross sectional area of the conduit. Where that breaks down is typically at the box connectors, particularly painted enclosures. And the threads on those connectors are not precision and often do not tighten well. One case I saw was on a 200A switch. there was a phase to ground short and the ring on the concentric knockout was completely blown out
Wrt untwisting wires if pulling Romex (nm-b) through conduit…. I’ll assume you are speaking of pulling multiple romex cables and not the individual conductors.
There is no NEC prohibiting pulling Romex through conduit. In fact, in some cases it may be required.
The CEC does not allow non metallic sheathed cable (Romex to you Americans) to be pulled in conduit. If there is a short section that requires mechanical protection, it is generally allowed to use a length of conduit. But then they call it a sleeve so they don't have to break their own rule.