[bat_sy]

I can answer for UPI. Unlike AliPay/WeeChat, the central agency (NCPI) only maintains the API. Businesses are free to develop apps on top. In India, there are 50s of apps enabling UPI transactions. You are free to download whatever app you prefer unlike AliPay/WeeChat duopoly.

[iury-sza]

Same for PIX. It's a payment protocol. Any fintech can build on top and support it.