Elena is only good on offense. She is way too squishy to be on defense (e.g. in raid defense team). She is the easiest 5* tank to face, tile damage from Kiril + Grimm + Sonya is enough to kill her fast.
So if you’re thinking of ascending her, she is only useful in offense.
I have both maxed and neither one are used in war (choosing an emblemed falcon over both of them)… but if you have to pick one, I’d go JF for his speed.
In my honest opinion, if you are looking for a war team or defence team, I wouldn’t do either. Wait it out a couple of months to see if you get anything slightly better.
However, if you are looking to increase Titan scores then Elena does plenty of damage.
And I would say JF in flank if you had Telluria as your Tank.
Good luck
If we ignore upcoming heroes you could pull I’d probably do Elena, in your position. I like JF a lot, but if he isn’t getting emblems and don’t be on your D team he only brings so much to the table. Elena brings way more tile damage than your current reds, and will be very handy for rush tournaments.
That being said, if you plan on pulling for either Tyr or GM in the next two months I would hold onto the rings for now.