Your simply assuming PLA is simply just going to let these bombers fly in?
You don't really stop them unless you launch first with a strategic attack on the U.S. heartland.
Last I checked the PRC has a explicit no first use policy.
Who said they would do nothing? The point is whatever they do likely won't matter.
Oh, and China's massive surveillance satellite and AEW network is just gone.
Iran had a substantial one too. It didn't really help even against the fairly weakly stealthy F-35.
Judging by the fact you assumed NGAD will be in service in big enough numbers to be relevant here hence it'll be the mid 2030s, how'd you intend to counter PLAN's 093B/095(Even if 095 does not appear for some reason and PLAN does not increase 093B construction rates there'll be ~40 of these by 2035) swarm in SCS or the AIP swarm?
I suspect the war will happen long before 2035, and likely within the next few years, actually.
How'd you intend to counter PLAAF again?
That's not the right question.
The question is what capabilities does the PLAAF have, that other air defense forces like the Soviet PVO didn't, that lets them stop the B-2s. The answer is "not much". A large orbital layer of SBIRS-LO type sensors may be effective, unless the B-2 does that thing it is designed to do and flies very low to the ground below the clouds, I guess. Orbital and over-the-horizon detection systems were factored in when B-2 was designed.
Are you assuming a smaller force of NGAD is somehow going to hold for useful amount of time against a numerically superior enemy with heavy backend support? or how'd you counter a possibly numerically and technologically superior PLAN surface fleet with massive underwater support?
"Technologically superior" it isn't. In some areas, it's parity. In most, it's behind. But not by much. Only about 30 years or so.
Chinese nuclear weapon stockpile is projected to reach 1000 warheads by 2030 with possibility of increasing beyond that how'd you intend to take all of these out in a single strike?
With a lot of small bombs that can be packed in large numbers in a big stealth bomber. You don't need to take them all out. You simply need to destroy enough that when they launch, and they will, the ABM system in place can degrade it enough to make your losses less than the enemy's. That's how you win a strategic nuclear war, which is the end point of escalation between a US-PRC war over Taiwan, and a pretty slim possibility (but possible nonetheless).
There isn't really anything the PRC has that keeps the U.S. from "escalating to de-escalate" to put it another way.
Their system and doctrine rely on second strike survivability yet you're assuming all of their planners are idiots and didn't think of this or possible counters?
I think they'll eventually get there but not in the next couple of years. We can check back in 10-15 years when the U.S. has more B-21s.
Also, if since we are already in the 2030s,
I think as time goes on the risk of war between the US and PRC will drop, as the PRC gains capabilities closer to the U.S., thus raising the costs of war. For now it's a very rough window because the PRC is reaching parity with the U.S. in a lot of areas like hull numbers and regional fleet strength. In the latter half of the next decade, the U.S. will be dipping below parity, which is the other dangerous period.
Right now the USN can only meaningfully contribute to the joint battle using submarine forces and missiles like LRASM or CPS. In the future it may not contribute with submarine forces in the SCS, or it may only provide strategic nuclear capability with the SSBNs, depending on how developed the PLAN gets. It will still have a lot of horizontal escalation capability, that the PLAN will never be able to match because it lacks the global empire of the U.S., though.
The horizontal escalation capacity likely won't disappear until after the war since a stronger China is frightening to its neighbors.
Now this could all be irrelevant if, say, the ROC surrenders after a week while the U.S. waits and watches (al a successful Ukraine SMO) or it peacefully merges with the PRC. Then the U.S. retreats to the Second Island Chain and the PRC does...whatever the PRC is going to do when it achieves victory, I'm not sure even they really know, tbh. They'll have a lot of military muscle to throw around and not much to point it at if they don't have a Gotterdammerung with the U.S.
what's stopping swarms of H-20s from counter bombing the US?
That would be an excellent counterweight on the "balance of terror" and effective deterrent. Shame they don't exist!