Neutral or +Spd/-Res Olivia??

I have 4 4* Olivias and I wanna merge them. I already merged my neutral Olivia by 1. I have another Olivia that's level 29 but I forgot her IVs, and I have one that's +Spd/-Res. I only want to use her as a support unit, so I do not plan to build her as much nor upgrade her rarity (I lack the feathers anyway lol). Which Olivia is better?