Trying to figure out why my Optiplex is slow

First time self-hoster here. I recently bought Dell optiplex 5060 Micro on ebay (6 Core i5-8500T 2.1-3.5GHz 16GB DDR4 512GB M.2 SSD). I’ve been finding the computer to be quite slow when compared to my old laptop (it has similar specs to the optiplex actually. I’ve run the CrystalDiskMark (picture attached below) and...