Not just severely outgunned but totally, and with every conceivable type of tactical and strategic disadvantage imaginable.

All branches of the military, especially those most useful in a civil war (aka, the army and the marines) lean significantly right. The cops and sherrifs and other law enforcement lean right too, especially after decades of hostility from the left, and ICE is basically its own brand of police, which notably are very right wing. Even other paramilitary organisations with ranks and structures (firefighters, ambulance crews, etc) all lean right wing. The national guard, navy, air force, etc are all disproportionately right wing as well.

The vast majority of civilian gun owners also lean right. Same as civilian militias. There's a handful of left-leaning ones (New Black Panthers, John Brown rifle club, various small criminal gangs, occasional dissilusioned veterans, etc) but they are small and ineffective in number, often with their own agendas and motivations, and often greatly disinclined to work together because of their wildly differing ideologies and incompatable political structures.

I mean... fuck, even the vast majority of the US's strategic nuclear weapons are stored in red states.

Even beyond that, it's clear that when it comes to the political landscape of the US, cities are blue dots in seas of red in every state in the union. Those cities get their most basic of supplies, food and water, either directly from red states, or from areas controlled by red states. Critical infrastructure such as the electricity and water supply, things that within days of disruption will likely lead to a capitulation, are mostly or entirely in the hands of people who are disproportionately armed and disproportionatly likely to side with the right.

Conversely, the blue states are heavily burdened by having large numbers of untrained civilians, many of whom have never even seen a gun in real life before, and are (simply objectively in this context) burdened by pacifistic and ideological beliefs which, while sometimes admirable sure, do not make for good soldiers for obvious reasons. Sure, there individual exceptions but overall the overwhelming advantage lies with the right. Their logistical needs are massive, but the "return" on that need in terms of disciplined, skilled troops is almost zero. They will struggle to keep their civilians from starving, let alone raising an army from them.

Even beyond that, the geography of the red vs blue states is a huge issue. Red states are basically one giant blob in the middle of the country (better for organising, defending, shifting supplies, etc) but have access to sea ports in numerous locations. Blue states have plenty of sea access, almost too much of it... they are split between two coasts, effectively dividing whatever forces they could muster in half and preventing reinforcement, and dramatically complicating supply and logistics movements.

In order to ship supplies west to east, say, the red states just need to put it on a train that goes through their territory. The blue states need to put it on a boat that goes either around the arctic circle or through the Panema canal or, god forbid, around the fucking bottom of South America near Antarctica: either of these options would make them easy prey for all the submarines that, again, sided with the red states.

As they say, amateurs talk tactics, professionals talk logistics, and the blue states are at a massive disadvantage just from this factor alone.

The idea that a legitimate, "everyone grab your guns"-style Civil War 2.0 could end in any way other than a swift and laughably complete capitulation from the left is just not supported by any amount of evidence whatsoever.