At its most barebones, an LSP can just be a regular LN peer that a user has a channel with and relies on for routing & liquidity management.
But yes, logic could be built into/on top of your node to try a payment, and if it fails, retry through a specific LSP. Or, you could have a list of peers you can reliably pay, that you pay directly, and if your destination is not in that list, you use the LSP to access the wider network.
At its most barebones, an LSP can just be a regular LN peer that a user has a channel with and relies on for routing & liquidity management.
But yes, logic could be built into/on top of your node to try a payment, and if it fails, retry through a specific LSP. Or, you could have a list of peers you can reliably pay, that you pay directly, and if your destination is not in that list, you use the LSP to access the wider network.