Military:
I will place China below Russia at the moment. Chinese military as a way more moneyed can afford more fancy weapons, but it make an impression of a toy army, as it lacks most vital elements to function in wartime.
Military logistics is abysmal, and untested, NBC survivability near zero, military hospital infrastructure rather low, supply stockpiles allegedly low, airfield survivability measures non-existent, rocade infrastructure, and military roads not there, but that's compensated by giant civilian road, and rail network, field recon is small, and untested. On this list, logistics is the biggest weakness. No matter how big your army is, you can't fight a war if your force simply can't reach the enemy, and sits in the field waiting to take a hit.
China's C3 is nearly completely electronic, which is a double edged sword in case of key officers being taken down, but an advantage if losses of officers in the field are high. China makes big bet on a small, and well trained elite officer core which will take over command in wartime from safety of secret bunkers. It's a very bold, and risky bet. Anybody in war with China will put taking down command centres as a top priority. I also see a risk of this impairing comprehension of field recon, and bottom up feedback in general. A beheading strike is the biggest threat to such structure.
With regards to offensive potential, China's force is all about delivering a first strike.
USSR prior to WW2 would be a pretty close analogy. When German came, it was a very rude awakening for them despite having a ridiculous numerical, and technological superiority. In first years of war they lost most of military assets without them firing a single shot. And Germans very well knew that time was playing against them. They were frightened with a prospect of Russians being able to organise their own organised first strike with all their material advantage.
All of China's potential targets are situated over bodies of water, and China's navy is too small at the moment. Just as with USSR, NATO has a total numerical superiority, and more ships than the enemy has missiles. But... NATO's naval advantage is disappearing by the day. China's naval buildup is very, very threatening. With China's steel output passing 1 gigaton, they can have more than twofold tonnage advantage over NATO by the end of the decade. Add to this that most of world's shipping happens within reach of China, they will have no problem requisiting just any amount of cargo ships under a gunpoint.
With regards to all above, China's current nuclear offensive capacity will only be able to inflict 20M casualties at most if used solely against cities. 20M dead is certainly survivable for US. If they will spent all their DF41 on military targets, they will still not be able to destroy a big enough portion of US military in CONUS to deter a retaliation, nor would they have the offensive capacity to follow up. The later though is changing rapidly with China increasing its naval tonnage. In other words, they can't invade US when NATO has naval tonnage advantage, but that is rapidly changing by the day.
This is all coming to US either stepping up naval buildup at the highest speed possible, or increasing its nuke stockpile n-fold to compensate for this weakness. With regards to conventional military force US, is very much safe.