He is 5-9 dating back to the 2016 season, Not sure if they D1 in his early years
I looked into it year by year for the last 20 years: 5-8 with D1 from 2016-2023, and D2 from at least 2004-2015 (not sure about years prior). Here are the D1 postseasons:
2023- 0-1 (Lost to Riverside)
2022- 0-1 (Lost to Fitch)
2021- 2-1 (Beat Aurora and Nordonia, Lost to Mentor)
2020- 1-1 (Beat Perry, Lost to Green)
2019- 1-1 (Beat Massillon, Lost to Boardman)
2018- 1-1 (Beat Fitch, Lost to Lake)
2017- 0-1 (Lost to Green)
2016- 0-1 (Lost to GlenOak)
From 2004-2015 Dover went 24-12 with a final four appearance in 2004. Another thing of note is that they played John Glenn nearly every year, as they met in the post season in 06, 07, 09, 10, 11, 12, 14, and 15- 8 out of 10 years from 06-15!.