WW2 is of a different era and things have changed now. The transition phase from ww1 to ww2 was massive and the same is true now.
your quotes about Russia France and UK are all correct but the matter of fact we as of now suffer from even worse issues and while their influence has waned it has not disappeared simply due to the fact that there is simply no one there to fill the power vacuum. So while its true that they are no where near what they were during colonial times or the world wars they are still a force and have influence in the form of soft power weapon sales and whatnot. hard power is now not the only metric but there are many ways to maintain influence too.
I don't know what version of galwan you have read but i don't see it as win of any sort. They lost more men true but then again they don't care about losses what they wanted to see our response and we decided to not retaliate. we didn't counterattack against their ambush neither against their land grab. The same is happening in Bhutan now. doklam was indeed better since we held our ground.
japan and Asean countries are past the point where they are willing to fight wars. 3-5 years from now you can be assured that these countries will simply turn into vassals as they are integrated deeper into the Chinese economic framework.
Japan has its own huge population issues and public perception that prevents them from playing any major role in the coming years. japan and korea's recent trade deals and the incoming pacts with china simply show that they are willing to accommodate to bejing. none of this countries rest assured will be fighting or will be in a position to fight in the coming years.
Japanese citizens will be the key to determining the success of the Sino-Japanese reset.
thediplomat.com
anyways i have found the Japanese to be willing to accommodate in existing power structures rather than carving their own place.
The only threat to China comes from India and USA and US as of now is a wild card as we will have to wait and see how the biden administration moves ahead.
As for war fighting capabilities as of now i am under the firm belief that do not have the training or experience to fight us or the US but this can change in the future as their forces continue to modernize.