blockchain smart contract wallet with hot wallet

I'm looking for a developer to build me a Smart Contract wallet (e.g. multisig feature). In order to interact with the contract a user will need to use a hot wallet (e.g. Chrome extension app that generates Eth addresses and also cryptography [Javascript Subtle Crypto API]. Most of the interaction with the contract will be done via the hot wallet, however, the final signature will come from a Relayer address. So will also need a basic backend site script that will act as the Relayer and interact with the Smart Contract Wallet - this can be done using Azure/AWS/GCP. The Relayer gets the approval to sign from a basic PWA or Android App that reads a QR code from the hot wallet and sends a HTTPS request to the Relayer. The Smart Contract wallet will only be for normal ERC20 transactions. The UI/UX is not important to me at the moment as this is only a prototype.