After DCing with @kyle, this is almost certainly it.

I verified that my LastPass export contains the key.

I (correctly) moved off of LP in late 2022 after the first hack and moved to Ledger / paper / 1Password after the breach.

However, I lazily never moved away from my primary hot wallet.

Its key was in LastPass.

here's yet another reminder:
if you ever put keys in LastPass - gtfo of that wallet. people are STILL getting hit in waves. there are probably still more to come

advocating for independent operators @ethstaker // stake responsibly //
be a kind human // slomad

Iirc vaults leaked but if you had a strong master pw unclear if anything to worry about, those could take decades to bruteforce

(I.e. 50+ characters, adding entropy every year for multi years)

Idk anyone with good master+sub-pws for secure notes who got drained

Nature of using a cloud service imo