Ok so I'm gonna ignore a lot of what has been said in this thread because id have to spend ages debunking a lot of misunderstandings of how the Mughal system worked and evolved, so I'm just gonna give my two cents with regards to op. But in short- succession Wars were actually very helpful for the empire, the only problem was Aurangzeb didn't let his sons do it properly. When Shah jahan died, you had four princes who had each spent decades managing vast amounts of money, rewarding loyalty, building alliances, finding a base of power they knew would support them. This meant new groups could keep being added to the nobility, and the top nobility was always being replaced and so were dependent on the emperor.
When Aurangzeb died you had a bunch of princes who were basically broke, couldn't promise anyone any rewards for following them, were too old to be inspirational, and a bunch of super rich nobles who Aurangzeb had favoured over his sons, who had no loyalty to any one son, and only cared about their own status, leading to the situation in the 18th century where no emperor had the power to challenge his nobility. Literally the only thing you need to have is Aurangzeb die 20-30 years earlier than otl and the empire is most likely to survive in top form for at least the next century.
Would this India be more decentralized (albeit united) and no large warfare with each other, than Qing China?
I think it could very well end up a lot more functionally centralised than Qing China in the 19th century, seeing that the Qing were limited by a commitment to minimal taxation, and that severely limited the central governments ability to do.. anything really, and each government official was forced to try and govern an absurd amount of people, forcing corruption. But on the other hand, I can see it functionally being a bit more similar to British India in terms of a large number of princely states especially in marginal areas, too small to do anything but support the imperial policy and military force, while the empire itself directly administers the most productive areas.
Would it be more advanced than Qing China was in the 19th century, with regards to industry, economy and military?
In terms of industry, most definitely, it's so well connected to the global world economy. If European companies can't establish territorial government that definitely won't stop them from continuing acting like companies and trying to expand their own industrial production in India, so even if no Indian merchant-nobles lead the charge in introducing new technologies, it's inconceivable that no Europeans would by the end of the 18th century. I also think Europeans would, if not setting up territorial administration, still be becoming more influential as members of the mughal nobility.
Like we said with the revolving door of the nobility, given the financial backing Europeans can offer candidates during wars of succession, European presence would strengthen imperial control , while the winners backers would find themselves integrated members of the nobility, bringing all their cultural and technical knowledge with them. There is no comparable avenue that allows Europeans power/money by strengthening the government in China, even when that would have been more profitable for them.
How would it affect colonialism in Asia, especially in the Indian Ocean area: Coastal India, Ceylon and South East Asia
Impossible to say- it definitely prevents any company from being able to humiliate China so easily. The Dutch might face a lot stronger competition in Indonesia and south east asia from the British if the latter can't focus on India. Whoever controls Indonesia would likely be forced to accept some level of vassaldom but that most likely just means they have to insert the emperors name in the khutba and mint mughal rupees in their lands, which is a win win, because the colonisers would want a more monetised economy anyway because it's easier to tax, and the mughals would be for a while at least, satisfied with their sovereignty being in their eyes so clearly accepted.
