When these trolls are everywhere just spamming Indian flags and doing nationalistic chest beating, then that perception will only go down as you correctly observed.How the world outside of your border perceives you is a part of soft power. In democratic countries public sentiment will inevitably affect policy making, hence if used precisely, propaganda can lead to positive sentiment > positive policy returns.
A good example of this is NATO inaction during 2014. Russia had flooded the internet at that time and led to widespread indifference.
NATO inaction in 2014 was not due to Russia flooding the internet with trolls, lol, and there was little the West could do apart from starting a war over Crimea - it was not an actual war zone like Donbass, it just switched flags overnight basically. Most of the "mainstream" support for Russia you see in the West is from far-right movements and it is due to the simple fact that it is a majority white country. China is not going to receive that white privilege pass from these rightists no matter how much they invest in soft power because powerful China is the total opposite of what they want. Nor China should strive to appeal to these people tbh, it is far more useful to build up soft power in the Global South.