That’s a neat thought experiment. You’d need the wallet holder to sign a lot of transactions for it to work but maybe that’d be enough of a reduction of crypto integrity for an attack to be successful - especially if the end game is a Coinbase cold wallet or something.
How many transactions are needed depends on how many bits can be sent home per transaction.
A Bitcoin seed phrase is 128 bit. 32 bit can be easily brute forced. Leaves us with 96 bit. If you can send out 10 per transaction, that is only 10 transactions.
Although I assume you'd be a bit confused why your cold wallet is taking its time to generate a hash or whatever with the 10 bits it needs to modify? I don't know what that time would look like but you'd start to question massively arbitrary delays like 10 seconds one time and 30 minutes the next.
