Custom Crypto Payment Integration

Hello,

I need you to build a custom payment option for my site to allow my clients to pay me with four specific crypto currencies without having to use a third party payment provider.

Here is how it should work:

1) Your script will convert the total amount from USD to the amount of crypto currency chosen (ETH, BTC USDT or USDC)
2) Crypto currencies accepted should be these four: ETH (Ethereum chain), USDT (Ethereum chain), USDC (Ethereum chain), BTC (native chain)
3) On checkout page: Allow client to choose which crypto currency he will use + Show chain name to send token (Ethereum or BTC) + Calculate exact crypto amount instantly based on current online price + show destination address easy to copy paste and in QR code format as well if possible so they can scan if they use mobile. The client should have 12 hours to send the amount seen on screen.
4) Detect the transaction on the explorer of the chain (Ethereum or Bitcoin) and redirect the client to existing THANK YOU page as soon as the first confirmation has been detected.
5) Send order details by email to client + admin (myself). I already have the email templates and script to send email to clients because my site does already have Paypal currently integrated.

Feature: I should be able to enter the BTC and ETH addresses that will receive the payments in a FILE or database. Tell me which option is safer so hackers cannot edit the file I will specify the list of Ethereum or BTC addresses my clients are supposed to send their payment. My site is hosted on PHP VPS and my another site is hosted with Go daddy windows version but it supports basic PHP because all my current pages are with .PHP extension.

I receive like max one order per day so no worry about mixing up orders. It's not like I receive ten orders per minute. You can always add or remove a few cents to the total amount to distinguish orders. I prefer to avoid databases because they may get corrupted, hacked or have connection issues. I like to receive order details in real time by email and do not keep backup on server.

I will send you the link of my site if you PM me. If I forgot anything in description above, please let me know.

Thanks