Good luck! I didn't know my 3rd great grandparents, and I looked for them forever with no luck. One day, a guy messaged me and said, "I'm a DNA match to you, but I can't figure out how. I know what family line you fall on though, maybe these links to records will help you out." It had my 2x great grandma, her parents, her siblings, her grandparents, their children, marriage dates, locations and addresses, signatures, etc. It happened so fast, I went from having nothing to more records than I knew what to do with. I hope the same windfall happens to you, it could be just around the corner.