> on LN the sender sees the node pubkey
...which might be a decoy
> just like a stealth address on XMR
...except that does not support decoys due to the lack of transaction chaining on monero. If Jimmy sends money to a monero "public address" he can cryptographically prove that the pubkey therein controls the money. (Btw, that is the first step of every trace, unless the tracer can find someone who already sent money to whoever they're looking for, which has the same result.)
Not so with LN: if Jummy sends money to a lightning invoice he does not know if the pubkey therein ever controls the money even for a second. It might be a trampoline node serving as a decoy recipient, because every lightning has built in support for this. It's part of the protocol design to allow this: thanks to how HTLC forwarding works, the recipient can always put a decoy recipient in the bolt11 invoice without the sender being able to detect it, and if the recipient does that, the decoy recipient looks like the recipient but never controls the money.