But where and how can I publicly expose this transaction?
You just did, not that it's private in the first place.
But if want to get it flagged, you must report the incident to the authorities.
My first 'sats' were just stolen again—straight from my PC/Electrum wallet

The issue is, it's a self-custodial wallet, so, its safety entirely relies on your own.
Read this disclaimer in their website:
electrum.org/#disclaimerIf you can read Python, you can verify their source code to see if they're telling the truth.
Anyways, finding the cause will not help you recover your bitcoins but it will let you learn what not to do in the future.
- First things first, is it a legit Electrum wallet, have you verified its signature? (instructions)
- How did you backed-up your 12-word seed phrase?
- And check if your PC is safe.