Many of these battles are extremely scarce on details on the battles themselves which is frustrating
One example is Assaye in 1804 where the British being outnumbered 3:1 and the Indians having FAR more artillery pieces on hand to bombard the British, were able to rout he Marathas from the field.
Another is Argaon where the British were once again heavily outnumbered but somehow claimed victory
When you strip back the raw numbers and start looking at quality of the troops on both sides in conflicts between company forces and Indian armies they are roughly similar. At Assaye the Marathas had 10,000 infantry trained in the European style of warfare. The company had 9000. The rest of the Maratha army was made up 10-20 thousand of irregular infantry, largely armed with melee weapons with no command and control. The cavalry was 30-40 thousand strong but again no training or organisation.
In this period morale was the key factor in victory. Napoleon said "In war, three-quarters turns on personal character and relations; the balance of manpower and materials counts only for the remaining quarter." The company army had developed a reputation for winning and paying their troops regularly. Company armies were confident of victory, well trained, well supplied and regularly paid. Maratha armies were the opposite. Fundamentally when company infantry attacked the Maratha line, the Marathas would break. Company lead regiments would take heavy losses in the approach but when in musket range the whole line collapse.