What to do with a +HP -SPD Elincia?

Usually I would recommend using a build that takes advantage of non ideal IVs but -Spd is almost crippling on Elincia since you miss out on Quading opponents. I have a +Atk/-Spd Elincia but she is viable with Death Blow. Still I would prefer a +Spd and if she wasn’t +Atk I would’ve foddered her for her Flier Formation. With weapon upgrades Palla and Caeda are very good red fliers and easier to merge/find optimal IVs.

Shes still good, obviously not optimal at all, but still good. Thanks to her weapon her offensive stats are still basically 37 36 compared to other brave weapon users.

All it means is that u cant use firesweep sword on her.

Her standard deathblow dragback is still good and optimal

U can go LnD desperation thanks to flier buffs

Or BA desp combo if u ever wana use her outside fliers and as a wall breaker for wary fighter amour.

At the very least...thanks to her +4 to hp she gains nice 58 61 bulk even with LnD for easier seting up for desp.

All that being said i still think caeda is better, i use her more than my "neutral" elincia

First thing first: there is not such thing as an unit becoming unusable with bad iv, he/she will just work a bit worse with the same set than normal.
I run a neutral elincia with L&D3 with a goad flier team and i find that most of the time she doesn't even need to quad to kill targets, if she is -spd maybe death blow will work better than L&D