For me, best way to buy bitcoins will still be the same old school way. Buying USDT via P2P & converting those to bitcoin. This way, I hardly have to worry about tax as the amounts I deal in will usually be below 1 lakh so it's fine until & unless I get the deposits from verified sources. In P2P, usually regular merchants having offline shops make payments so that can easily be reported as friendly transcations to avoid tax.