Is it possible to understand where the coins were sent, or are they lost?
For that, you need to post the transaction ID issued by the pool.FYI, that "Lightning Node ID" is a compressed public key derived from your wallet's "lightning_xrpv" key.
If I were to guess, the pool might have derived an address from that public key to send your bitcoins, but don't take that as an answer yet since it's a guess not based from actual data.
Note: if it blindly accepts invalid recipients like your Electrum's lightning node id, chances that it's either poorly written or scam.
Care to send the name of the pool that you're talking about and how did you mined there?
