Electric Revelation
Instant
As an additional cost to cast this spell, discard a card.
Draw two cards.
Flashback 
(You may cast this card from your graveyard for its flashback cost and any additional costs. Then exile it.)
Liiga Smilshkalne
The List (PLST)
• #J22-526Rulings
If you cast Electric Revelation using flashback, you must still pay its additional cost of discarding a card.
(wotc • 2021-09-24)
Rulings
If you cast Electric Revelation using flashback, you must still pay its additional cost of discarding a card.
(wotc • 2021-09-24)