Nerf Erron's F4 Already
You are right, perhaps a complete change to Sonya's air launcher would be too much. However, I wouldn't rule out the possibility of NRS nerfing this aspect, since NRS did it to Aquaman in IJ2 (who had one of the highest dmg potential at the time), and given that Sonya is also one of the most damaging characters in Mk11.
If Sonya is meant to be a rushdown character, then her current projectiles has to be nerfed then, perhaps with more recovery like you mentioned, or maybe her amplified energy ring becoming a high (like kitana/liu kang), or even increasing the start-up of her projectiles. Not too drastic, but it will do.
Yeah and then they gave it back to him because someone finally realized, aqua man literally only has trident rush now.
She should get the black adam treatment with damage reduction and projectile nerf. That's it. I don't want a deadshot is useless disaster all over again.