I think he'd provide good cover but if he wanted £350k a week at Arsenal it would be a non-starter as a deal. He's 29 as well.Soon as sterling released that statement I immediately said arsenal will come calling. Arteta cannot resist any cast off out there from his time at city in his bid to recreate city 2018.
Sterling could be a very potent player for Arsenal but your fan base wouldn't give him the support and time he would need to become that player, you'd Xhaka him before he found any kind of form.
Of the 3 options above Osimhen would be the preferred one.