Lingua Franca in India will remain English. Hindi - I have my doubts.
The BJP wants it that way of course, selectively berating local languages, popularizing Hindi and then exporting cow belt people all over the map in West Bengal, the entire South (including Andhra/Telengana), Maharashtra as well as Punjab. Auto/Taxi drivers in Bengaluru won't even talk to you if you speak in Hindi.
There is strong pushback already against "Hindi Hegemony" and "Hindi Imperialism". These are grassroots movements by educated folks in the above states - led by WB firebrands.
This is the entire (single) reason Bangladesh broke off from Pakistani leadership.
I can create a thread and post videos if you guys like - better not to ignore an entire grassroots movement by denying its existence.
People in non-Hindi states do not want to be turned into second class citizens in their own states by imported Bihar and UP populace. Ignoring this trend will be problematic for the BJP. Hoomki-Dhumki se kaam nahi hoga.