What were the TACTICAL advantages of the British in the Anglo-Maratha Wars? The Marathas had several times more men, a higher ratio of artillery, a higher ratio of cavalry, and even flintlock muskets for most of their infantry later on. How did the British still consistently thrash them tactically?

The thing is that you're looking at things by the numbers, and sometimes that doesn't really work. I asked a related question about Indian units raised in the European style, ably answered by u/MaharajadhirajaSawai; no doubt they have more thoughts on this specifically, but for now, that most excellent treatise should get you most of the way to an answer, OP.

And as ever, should anyone else knowledgeable of India have more to contribute, please don't let this post stop you!