Ovinomancer
No flips for you!
And, how many 5th level slots have you prepared -- I'd like to take the same number of rounds of preparation with the wizard.No?
Sorcerers have a lot of high level spells slots. It's called Sorcerer's Flexible casting. Converting low level spells slots to a higher level spell for a worth battle.
The Sorcerer potentially has 8, 5th spell slot.
They can't choose 1 on portent (It has two d20, not 1), also, Magical Guidance to reroll a failed counterspell's check. You can't use reaction while surprised and yes, the sorcerer can upcast it to level 5.
And no, Shield won't save the wizard against that alpha attack.
The Wizard is dead.
Beside, most likely the Wizard has beaten you because you've fallen for the Orc in a Robe ploy he though up as a lark to use on 8 INT 8 WIS sorcerers. A little 1st level illusioning and you're snookered into alpha striking the Orc while the Wizard guffaws and polishes you off. I mean, if we just get to make things up after the fact?