is there a reliable way to detect if a wallet address has a smart contract attached to it ?

Hi So the context is that I'm building a wallet with some safety features. One of the exploits I want to help people with – is the kind where scammers claim they have usdt in wallet but don't know how to withdraw it. And you need to send gas fees to it.

E.g. https://imgur.com/a/3Chi5TG

https://twitter.com/beastincrypto/status/1546937627194150915?t=ZAi3yUjZlh4YNUoB-E1H3w&s=19

But in general, I want to flag anytime there is a wallet address that is attached to a smart contract.

Now it seems that this is very hard to do. There are previous posts that show "iscontract" is not reliable.

https://www.reddit.com/r/ethereum/comments/916xni/how_to_pwn_fomo3d_a_beginners_guide/

Is there a free api (like infura,etc) or any code that will help detect this ? My app is in flutter, but I'll figure out even if ur method is any other language