I think on average they're pretty good compared to most teams. You don't really let Mixon have four games of 100+ rushing yards if it's a really bad OL.
Nothing close to what the Dolphins, Rams, Bears, Cardinals, Seahawks, Carolina, etc. are working with. Like it's not even some plays those lines are bad, it's every snap those lines have a lot of problems and potentially get their QB's killed and zero running game.
Maybe not the amongst the very best (Lions, Colts, Eagles, Bucs), but still top ~10 in the league which is why I think Stroud and Mixon can go to work there.