Hey @Jiten,
From my prior experiences, I can recommend that choosing IMPS/NEFT/RTGS as payment mode should be left up to the user.
Why?
There are multiple payment systems & investment options which do not accept IMPS as payment mode but do accept NEFT/RTGS.
For ex-
BSEStarMF (backend for multiple MF investment platforms) does not accept IMPS as payment mode but NEFT/RTGS is supported. If payment from a Jupiter account is made automatically using IMPS in such cases then the user would have to unnecessarily go through the refund loop.
I think ICICI Bank has handled the payment mode selection between IMPS/NEFT/RTGS on their UI well. Jupiter team can check that to see if some inspiration should be taken from there.
Happy to chat with your product team if more inputs from my end can help 