bitcoin core – How to develop a crypto exchange leveraging on third party API like coinbase, blockchain.com

I got a request as a developer to develop a bitcoin exchange site like https://mypatricia.co/ or https://instantcoins.ng/ I am to leverage on third party API like Coinbase, blockchain, it could be anything reliable API.

Users will be able to buy and sell bitcoin. For instance USER A makes an offer. USER B is interested in USER A’s offer. When USER B clicks a button, with be a switch from USER A’s wallet to USER B’s wallet. Before the EXCHANGE is done. USER B is prompted to make payment in local currency.

I have been looking at https://developers.coinbase.com/api/v2#introduction https://api.blockchain.com/v3 I dont know how to go about it.

Is there any other better ones to work with?

There will be some other endpoints like

Where users get list of their orders
check wallet etc
I will appreciate your contribution