This will hide your phone number.
Eg: My UPI id is sudshekhar.cheq@trans.
Most other UPI apps allow you to create such handles AFAIK.
Nowadays, you can also keep your bank details private by using UPI with a wallet instead of savings account.
Banks / UPI vendors have to comply with very strict data regulations and the confirmation of a "data leak" is enough to attract heavy penalties from the NPCI and RBI. Most banks and UPI service providers will never risk it, specially post the DEPA guidelines which have recently been adopted.
Using Cheq, you can keep your bank account plus mobile number secret. Everyday small value transactions can also be consolidated separately from your main bank account.
I don't think anyone is selling data in the UPI ecosystem but if they are, that's a very short-sighted strategy to make money for sure.
UPI payments also ~~leak~~ share the person’s full legal name on transactions…and the phone number.
[1]: https://scroll.in/article/1045536/are-your-upi-payments-farm...
Legal Name -> Yes, everyone gets to see your full name post scanning the UPI payment app.
But this is a feature not a bug. Since in most cases I want to confirm the identity of the person I am paying to.
And allowing people to display any name as their UPI username will lead to much more identity fraud than you can imagine.