The literature from several websites says that the galls will not harm a healthy established tree, so there is your answer. Has the tree been in that spot for a full season or two? Did it appear to be in good health prior to leaf drop?

Here are two articles about galls on oaks. Both are very informative and the life cycles of the wasps are quite interesting.

Galls on Oak Leaves and Twigs | Horticulture and Home Pest News (iastate.edu)

Bulletgalls Targeting Oaks | BYGL (osu.edu)

If your tree appeared to be healthy this last summer it seems that the best thing right now is just to wait and see. The odds are it will leaf out in the spring and be fine. If not, it can be replaced in the spring. A spring planted tree just needs a bit more vigilance to be certain it gets enough water during our usual summer dry periods. Good luck!