This is a good summary that I think is accurate. Not trolling attempt and built from researching this issue for last three months and reading everything both sides said and even foreign information. I think this version of explanation fits all the real information and official disclosures.
India built new camps and sites from 2019 which started encroaching towards China's claimed point which are to Galwan river and Pangong Tso finger 4. These Indian build up went for half a year and then China responded by doing similar build up in 2020 until April when some things started and more confrontations between soldiers on both sides.
These confrontation began happening more and maybe gotten worse. Chinese claims is after May fight where a PLA communication soldier was beaten by Indians in the famous video of many Indian soldiers beating the PLA soldier, PLA captured some Indian soldiers which is the famous photograph of Indians soldiers being tied up. The PLA soldier being beaten was before the PLA capture of IA soldiers in May. However Chinese reports say the communication officer later died due to his injuries days after. At this point according to Chinese side, Indian army suffered only injuries and being captured but no PLA killed any IA soldiers. After the first two military talks, both decide to remove their forward build ups.
This is when things get into a mess and confusion. Chinese side is suggesting this is the June events happened. Commander Babu was forward patrolling and as Chinese PLA moved some stuff away from Galwan side, some Chinese construction crew members were still guarding some left over equipment. At this point Babu decide for himself against IA higher orders and started arguing with the crew and the few soldiers still there with the small construction crew. These construction workers and the few PLA soldiers there eventually gotten into the fight with Babu and his men, then PLA sent backup and more Indians also arrived. The fighting in 15th June started and went into the night for just under one hour where PLA got upper hand and killed Babu and two other IA soldiers. Other IA soldiers had injuries along with many people including PLA side. When it is clear Commanding Officer was killed, IA soldiers some surrendered and these were the 50 captured and some ran away who accidentally fall down cliff and some jumped into the river. The more than 20 other deaths were due to cold weather and injuries. Chinese side did not help those who left but did help the captured ones. Chinese side also suffered injuries and possibly some deaths. Chinese claims a few PLA soldiers later died in hospital from their heavy injuries. The number they are saying is 2 at the moment. However this is internal rumors and some people suggesting that many PLA had serious injuries were treated but 2 so far have succumbed to injuries. Diplomats communicate this to peers but Chinese news and global media do not wish to make situation more intense like already is in India. Saying to India people now officially 2 have died and rest of injured will likely recover is pointless. Indian diplomats know the real answer. Not saying this helps both sides find solutions. Saying this can only present more obstacle for both sides' leaders. Also many from both sides who died have died after fighting maybe a day or more after.
The Indian army did not come to rescue the men who ran away. Many were later found in different places. This is why the death count went up as new men were found until eventually the count is officially at 20 in total where 3 were killed by PLA and rest by accident. The 3 includes the Commanding Officer who PLA hold responsible. He may have been executed by bullet since his actions were also against order of IA in both side's agreement.
This incident made the May agreements very difficult so only now we are back on track from May talks. However both sides view each other in different light now and Indian media has let this get out of hand for Modi and more difficult for Modi to make moves. Opposition also screwing Modi every way even when he does necessary and correct moves now. Result is India is high on trade war talks and only will slowly get back to normal. If they want to go domestic, they should try and China will respond anyway to trade issues and probably will ban investment into India even if India doesn't ban first. War is now 100% impossible. Both sides reach certain agreement but to be honest future development is going to be interesting. Both sides are becoming further enemy status even if this thing in May was small and June was unfortunate.
Buffer zone now created but India has lost more from buffer zone even though China has now moved away from finger 4 and PP14 and PP15. India claimed until finger 8 and all of Galwan. The buffer encroaches more into Indian territory simply due to India's claims much more and further than China's claims. In the previous no man's land, India claims almost all of it while China's claims are to roughly half line. So now with new established buffer zone system, India's total old claims is now out of reach totally for India. China's claims until half way lines at both areas. Back to no-one owning the buffer zone again. Both sides will focus on their long term power again. So the May fighting turned to June fight which turned to regional politics which China is using now, this is by unifying the voices of Pakistan, Nepal, Bangladesh, and maybe in near future even Bhutan. China and India are currently both talking to Bhutan maybe over arunachal pradesh border dispute purposes.
Indian military has totally moved away from LAC which is what China wants. PLA seems to have moved back from those forward point now too. Whatever agreed between us seems to have taken us now back to before India's buildup in 2019. So China in this way achieved objective of making India remove those 2019 build up towards Chinese claimed LAC points which are Galwan river and finger 4. However seems like China is not staying in these forward points now either. They shouldn't stay there anyway as long as India is not close to those points, they have achieved objective. Why should PLA stay forever camping on finger 4 and Galwan river?? Some Indians interpret PLA move away from these two spots as something. Remember this, 2019 Indian positions now gone, new buffer zone created, India moved back even further behind where they were in 2017 on LAC. PLA move away, India starts chilling and relaxing and stop demanding Modi go to war and stop making long term noise. If PLA keep staying there, Congress party will push Modi to war and BJP will lose election. Cause more trouble ongoing. This way is China's dis-engagement offer to Modi which he and the diplomats accept immediately.