One thing I can certainly say, for Infinia upgrade 7.5L spend is not mandatory.
Background: Back when Covid hit HDFC were offering DCB and Infinia LTF. I was offered DCB upgrade from my Regalia which I refused and asked for Infinia, which they refused (I regret this)
Fast forward to 2022, I requested for Infinia, to which I received the boilerplate reply , need income of 3L+ and its invite only.
After the pathetic condition of Regalia, I reduced my spending in the card to 1.7k per month. I asked my RM for Infinia, she said not possible. From then, whenever she called I would request for Infinia
In mid 2023, she suddenly said let's see what I can do. I got a call next day from someone in Mumbai CC division who asked me to send a signed copy of upgrade form. And lo and behold, after 2 days of sending the form I got my Infinia delivered FYF.
I don't have spend of 7L across all my CCs, leave alone only on HDFC. Nor my salary is anywhere near 3L per month. Yet somehow my RM managed to get the approval.