I don't think the Bills need a dominant offensive line. What so they can run the ball and take the ball out of Josh's hands? Nah. Running a lot is for losers.
Just be decent in pass pro and you're good. If Doc is correct and the fallback is Williams then he fits that thinking. Kromer will help too, you've ignored that. The OL seems fine to me. Upgrade it for what purpose exactly?
I feel the same about corner. Early in their tenure Derm and Frazier were forced to start an in-season FA called Ryan Lewis at CB and you couldn't tell the difference. The Bills have Tre White and Dane Jackson. They're mostly good. They need a depth piece who can maybe start early in the year if Tre isn't quite ready. Draft one in the 3rd or 4th and be done with it.
There's a lot of concern going around over these perceived needs and yes they need to add decent players but these aren't spots where they need all-pros.