Cannot sign a UserOperation for gasless approve + swap with MetaMask Stateless7702

[ctb0k33]

Hi MetaMask team,

I try to build a gasless atomic approve + swap flow for a MetaMask EOA that has already delegated to the Stateless7702 implementation.

The intended flow is:

User signs a UserOperation
→ External bundler submits it
→ External paymaster sponsors the gas
→ EntryPoint executes approve + swap

Using @metamask/smart-accounts-kit, the canonical EIP-712 payload sets verifyingContract to the delegated user EOA. This appears correct because the Stateless7702 implementation executes in the EOA's context.

However, MetaMask rejects eth_signTypedData_v4 with this error:

"External signature requests cannot use internal accounts as the verifying contract."

Using the Stateless7702 implementation address instead allows signing, but produces an invalid UserOperation signature because it changes the EIP-712 digest.

I found the related restriction here:

#5470

Could you please clarify:

1. Is raw UserOperation signing for a MetaMask-managed EIP-7702 EOA intentionally unsupported for external dapps?

2. What security risk is this restriction designed to prevent?

3. What is the supported integration route for a dapp to implement gasless approve + swap using its own bundler and paymaster?

4. If wallet_sendCalls is required, how can the dapp specify an external paymaster?

Thanks !