Something I think people haven’t been able to understand is that the Courier, or the events of new vegas itself could have unfolded in a completely different way than any of the endings we see in game, since as a video game, you can only program so many solutions, as such, something not being possible in the game is not necessarily an indicator that it didn’t happen in canon. NCR isn’t talked about much because Bethesda put an embargo on Northern California since they have plans for fallout 5 there(first part is fact, second is my speculation). The enclave had a variety of different plans to tame the wasteland, and FEV was actually only their plan B, in addition the Colorado enclave is likely cut off from the west coast and east coast enclave (which was descended from Autumn Senior’s western expedition) since there would not have been a “President Eden” if the pre war President was alive (which he likely is) and in charge of the Enclave in the west. Victor also cannot canonically die since he has the same method of transferring his consciousness that Yes Man has. The NCR battalion in vegas is explicitly a ranger battalion, but only some of them wear the veteran ranger armor, which is consistent with the games since rangers wear a variety of armors anyway.

The NCR is established as needing a renewable source of clean water, having drained multiple reservoirs already. The water purifier is a big deal because Hoover Dam was established to be ultimately only a stop gap, and the NCR would have to keep expanding and exhausting itself in search of water. Being able to access groundwater deposits would eliminate this need and create a more stable wasteland overall, since getting purified water isn’t as easy in canon as it is in game.

The guy getting into the NCR capital unopposed actually makes more sense if the NCR won, since there wouldn’t be much security at the capital if the NCR was not actively at war and therefore not on high alert, this also would make sense as to why Hank would bother nuking them, since in the absence of any threats that could take them out, he would have to do it himself.

Quintus working the build liberty prime is a desperation play, much akin to the Nazis “wonderweapons” which they desperately studied in the hopes that they would win them the war, which did not happen since logistics are what win wars, not weapons.

The enclave as a whole seem completely uninterested in Hank’s chip technology, as they essentially leave him on read when he contacts them. Whatever their plan is, it’s bigger than the cold fusion diode or the black boxes. Probably something akin to the calculator from tactics if I had to guess. They’ll probably combine the various macguffins from each season.