What’s in it for the bank? How does it recover these costs? Do they charge monthly fee?

With chargebacks, the customer's bank will (attempt to) reclaim the money from the vendor's bank.

For credit cards the credit card issuer also shares legal liability with the vendor for purchases over £100.

https://www.ukfinance.org.uk/area-of-expertise/cards/chargeb...

They usually charge a small monthly fee if you want a credit card. I assume successful fraud is just an operational cost like all the others.

In the UK credit cards (as with almost all bank accounts) are usually completely free if you pay the balance in full every month. New accounts frequently come with years of 0% interest on balance transfers. They are also required by law to be jointly and severally liable for the completion of your purchase contracts with the seller if between £100 and £40k.