out of curiosity, i did some research on the topic -- things have changed since i retired. for one thing, Gemalto is gone - a search gets me links to extended/legacy support, dead web pages, and etc. oh well, these companies last about as long as cicadas in August. like everything else, the tech has been taken over by China. God bless the infinite stupidity of our American overlords.

and these little chip cards are in all kinds of things now, including crypto wallets. oh well, again. hotel room keys, your new car 'keyfob', all those 'smart' appliances ...

if you're willing to risk something like $100K, you can probably buy a batch of (1,000? 10,000?) prototyping cards, along with their secret keys, from a vendor. (but not the manufacturer key, so...) you can put apps on the prototype cards. you can get some development tools:
https://duckduckgo.com/?q=smartcard+prototyping+tools
and carry on.

step 3: ???

and PROFIT!!!

One thing you cannot do with this technology is repurpose an old SIM card, bank card, or hotel room key. This stuff is designed to be thrown away.