this is still a developing developer eco-system. from my perspective you have 2 options, either use

https://www.npmjs.com/package/@bsv/sdk

these are crypto primitives you can build custom wallets with, thats what we're relying on, you can build a single address wallet with a single key, the hard part of doing this is you will have to build utxo management, which is not trivial

there is also https://github.com/bsv-blockchain/ts-stack/tree/main/packages/wallet/wallet-toolbox which is a more full featured wallet which follows a new wallet to app interface called brc100 which i have not worked with

id def have a chat with your ai about those two