I mean you can look at some of the previous QBs taking in the 1st round in recent years and see that Ewers is a no brainer. I understand it's a deep QB draft but the only guys that should be taken ahead of him is Caleb and Drake. Regardless his plan is to enter the draft this year.
I'm not sure why you are such a fanboy for a kid that has yet to take a meaningful snap in college but no, Sark would not push Ewers out for Manning who is a complete wildcard at this point and it isn't even guaranteed he is QB1 next year.