If you want to do it I’d suggest to clone the system first using Acronis or other cloning/backup software, there are some free options for cloning.
If you use the ‘legacy’ firewire driver, it’s not in windows 10, you need to install it here: https://support.microsoft.com/en-us/help/2970191/firewire-port-based-device-does-not-work-correctly-in-windows-8-1-or-w
Possible problems are some plugins calculating a different hardware ID for your computer and Windows 10 might even give your computer a new hardware ID causing any plugins that are linked to that to stop working.
iLok. If you use iLok, you will need to update it. Some iLok plugins that work fine in Cubase 10 on Windows 7 don’t work properly on Windows 10 unless you grab the latest version but in some cases the latest version may require a paid update which sucks but I’ve found jBridging them even if just going from 64 bit to 64 bit but via jBridge works for some reason. Steinberg never seemed to fix or the issue. There is a plugin some people had success with using to make the other plugins work. I think it is Soundtoys Microshift. Loading it on the control room mixer leaving it powered off made other plugins work. The reason why and how is unknown.
I think the reason that most people would suggest doing a clean install is because you will be forced to download and install the newer version of most plugins which will most likely be more compatible with the extra security of Windows 10. Also, it stops any bloatware, old drivers, viruses and issues from your previous version of Windows being carried over to the new system but if you back it up first using something like Acronis and make a bootable USB drive or partition to boot from DOS or UEFI and have the backup on an external hard drive or another partition to your C drive, you can wipe and restore the C drive back to how it was if it doesn’t work out for you. I did a clean install. It’s better as all the plugins are on a newer version now but waaaay more time consuming if you have a lot of plugins to install.