I trade large volumes too, but I only convert to INR when I have to pay bills, etc rest is always in USDC / BTC. I think the situation for India is too shaky at the moment and in some cases you are automatically flagged for dealing in crypto (some of my friends have been locked out of their own bank!).

To answer your question: If you are moving large BTC >-> INR to / from your bank, you should open a current account, this will only remove of certain limitations in the savings account.

Regarding taxes, you should consult a CA. I used ClearTax and they were very helpful for gst / tax.

TIP: For safe and anonymous P2P exchange, you can try https://megadeals.io.