Definitely avoid that drvhub site.
Once you've run the exe, rather than "installing", try the extract option, extract the contents to a folder. Then from device manager, right click on a device, update driver and choose browse my computer, point to the folder. This option may work. Start with the NIC, the iLO is less important as it's just a way for the OS to communicate to the iLO and it isn't essential.
The dev/ven you sent is for the controller IC on the NIC, this is used in many cards. Your blades actually have a NC551i rather than a NC550SFP, it doesn't matter too much but you may get better luck searching for this term. This is the latest driver for that card for Windows Server, it only goes up to 2012 R2 but it may work.
You've got plenty of blades so it can't hurt installing Server 2019 and seeing what it finds.
Once you've run the exe, rather than "installing", try the extract option, extract the contents to a folder. Then from device manager, right click on a device, update driver and choose browse my computer, point to the folder. This option may work. Start with the NIC, the iLO is less important as it's just a way for the OS to communicate to the iLO and it isn't essential.
The dev/ven you sent is for the controller IC on the NIC, this is used in many cards. Your blades actually have a NC551i rather than a NC550SFP, it doesn't matter too much but you may get better luck searching for this term. This is the latest driver for that card for Windows Server, it only goes up to 2012 R2 but it may work.
HPE Support Center
support.hpe.com
You've got plenty of blades so it can't hurt installing Server 2019 and seeing what it finds.