If we play the 352 then I'd be happy with Sterling playing off Aguero or Jesus, but you're right, seeing Sterling lead the line for any length of time wouldn't be particularly comfortable, but how many other positions do we have that much depth in? If 2 keepers get hurt we're in trouble, 2 full backs and we're in trouble, 2 CB's etc.
A little bit different maybe, because of the injury record of Jesus and Aguero, but a lot of fans would have been unhappy to see Kelechi playing upfront for any long spell last season too.
Silva has experience being a false 9 for Spain, KDB could probably do a job in a pinch. It's a bit of a risk, but probably a manageable one. If Sanchez & Mbappé both go elsewhere, Id definitely rather go into the season with the current squad then quickly buy any forward as a placeholder just in case we have an injury crisis.