All great above!!!
Find the closest oaks and cut the hickory next to it extremely hard. For oak regen - leave it more of a mess so oaks get more of a chance to get going. Whites might take 2-3 years to seed but other oaks will be more frequent.
I would plant in it & not just on edge. I’d much rather plant “way too many oaks” than not enough. Always can thin em & u will lose some along the way.
In areas void of oaks or wanting to speed it up…. Thin the hickories hard & then it’s a “preference”: can interseed piles of acorns (numbers game), can plant oak trees & use the tops & brush as cover. Or, plant oaks and tube/protect them. If it’s upland like I almost sure it is…. Do a big variety of oak: red, white, chinkapin or DCO, burr, shingle, swamp white & maybe a hybrid. Reds like N facing a bit better & drainages. Do a lot of different varieties though.
If this is say “5 acres” ….. cutting & planting trees could be done in a weekend if u reasonably fast. I’ve done every method above. I suppose if I were to do it again, I might try some #’s of trees with hiding them in tree tops but I likely would spend the time tubing or protecting a hundred or so. I’d keep eye on them & each year I’d order more trees to add as needed or keep direct seeding until had successful stand. Not that hard or time consuming & u must spend a few years keeping eyes on it and NOT GIVING UP.