HP forums are full of users complaining that HP printers are taking a long time to start printing after a job is sent to print. Windows 10 is one common characteristic of these setups. I haven’t found a solution that worked for several HP printers I came in contact under similar conditions: advanced networked HP printer connected to a network with Windows 10 clients.
Eventually, I arrived at this workaround: disconnect the printer from the physical network and use the printer’s WiFi connection instead. Surprisingly this worked for all cases.
If you have an HP printer both with WiFi and LAN, try using WiFi. Your experience with Windows 10 might improve dramatically.