Which account does protostar deploy command from?

protostar deploy sends unsigned deploy transaction, hence it doesn't use any account. Currently deploying on goerli doesn't require gas. https://docs.starknet.io/docs/Blocks/transactions/#deploy-transaction

I want to deploy a contract from my own argent wallet I would need to declare + sign a transaction & I guess use the StarkCurveSigner. What are your thoughts?

Yes, you need to use declare and invoke and sign the invoke transaction. The declare transaction doesn't have to be signed for the time being.

However, the current version of Protostar doesn't support signing declare, and invoke transactions v1. This should be fixed in the nearest release (which should be released in this or next week). For the time being, use can use the official Starknet CLI.

This answer was originally posted on StarkNet Discord