There are few client which depends on Bitcoin Core (such as LND and Core Lightning). But i don't expect any of those use Bitcoin Core wallet since it can't store LN-related data (e.g. channel state, LN transaction/routing history). At very least, i'm sure Core Lightning has it's own internal wallet.
Isn't it a confirmation that we need an intermediary wallet to use the lightning network? In other words, there's no direct access, but we must necessarily use a bridge whenever we want to switch from one to the other. So, there's waters between the layers. Is it correct?
Wrong, no intermediary/bridge is needed unless you use third-party or custodial service.