Card to card online money transfers

You need to find a card processor/acquirer that has implemented the relevant products/services from Visa and Mastercard and work with them to set up a card-to-card programme. You can either whitelabel the acquirer's license or get your own license.

Can share a few names that IIRC support this, if @Admin could please move this to Mentor Group first?

There are different ways to do card-to-card transactions, from the older solutions like OCT / CFT (Original Credit Transaction / Credit Funds Transfer) to the newer Mastercard Moneysend and Visa Direct. There are pros and cons to both solutions.

IIRC, these are some that are able to offer some or all the services and can do custom card programmes:

decta.com/paynetics.digital/transactpro.eu/en/emerchantpay.com/transact.eu/dbs.com.sg/sme/dbs-forms/day-to-day/merchant…ervices.page
The first five have a pretty high risk appetite (for the right volume). DBS is only suitable if you have a presence in Singapore/Asia, preferably with a local license or license in Labuan or Hong Kong.