I'm not sure if it's appropriate to show most princely states as political entities on the same level as the provinces. I've done some reading on this in the past to try to make sense of what was going on there, although right now I'm mostly working off of a Wikipedia article so take all this with a grain of salt. But anyway, my understanding is that most princely states were administered under residencies or agencies that were subordinated in turn to provincial governments. The exceptions to this (again, per Wikipedia and my memory) were 1) Hyderabad, Mysore, Jammu & Kashmir, Baroda, individual princely states that had direct relations with the Imperial government, and the Rajputana and Eastern States Agencies, which were independent of any provincial government. In the 1930s, apparently pretty much all of the princely states were separated from provincial authority, but were still mostly administered as part of broader agencies like Rajputana and the Eastern States.
The problem is that the princely states were, I think, considered separate from the provinces in a legal sense. The implications of that are honestly beyond me, but in my opinion most princely states should be considered second-level administrative divisions, so if they're shown at all they should be shown in that sense. This does raise the question of whether a WorldA map of the Raj should also show provincial districts, which is a whole other can of worms.
Here are some pretty detailed resources on historical India:
https://dsal.uchicago.edu/reference/schwartzberg/
https://dsal.uchicago.edu/reference/gazetteer/