Thanks for thinking of me. I thought about trying to think of something I could add but in all honesty the changes are so fundamental, I could say anything I wanted at all really
Personally I don't think the Umayyads had anything like the capability to press into India beyond, if they're lucky, Gujarat and the western Thar desert. Even otl they were very overstretched, and simply didn't have the resources to wage large campaigns at the edge of empire when they have much more enticing targets and pressing concerns with Rome and Europe. Pressing for control over india means abandoning Iberia and the Maghreb, and I don't think that's a trade the Umayyads will risk given the uncertainty of success.
I also don't think that in the event of an earlier Muslim state establishing itself in the subcontinent it would have significantly better luck converting people than the Turkic sultanates a few hundred years later. Sure you might get perhaps 50 percent muslim over a thousand years instead of 30 percent as otl, but more than that seems unlikely, and it would still be in the more marginal areas where there wasn't really any established Hindu institution. I don't think a hypothetical stronger Muslim demographic would make the subcontinent tend more towards unification, or lead to the end of the caste system, which was incredibly resilient.
What I will say though, is that even disregarding all these issues with plausibility, I think it's incredibly difficult to speculate on an Islam which draws so heavily on Indian traditions from the get go. The Islamic schools of law would be radically altered, and it's also incredibly unlikely that early Sufi metaphysics develop in the same way. At this point, Sanskrit is still going very strong as a language of the elite and isn't as vulnerable to replacement as it was by Persian in the later middle ages.