I would check Device Manager and see if you actually have anything that is showing driver issues or using only a generic driver.
Windows 10 will automatically install new drivers when it actually needs them. That has nothing to do with the optional drivers in Windows Updates. The optional drivers are drivers where your system already has a driver installed for that device - it's simply giving you another option in case the one that is already installed gives you problems for some reason.
I let Windows install Realtek sound stuff because every time I've manually grabbed Realtek sound drivers and installed it messed up the audio in Hunt:Showdown .. But Intel NIC, AMD chipset, GPU .. I go to AMD.com or Intel.com to grab updates.
Depends. With some, I use the ones via Windows Update. Others, I install whatever the manufacturer driver is. It usually comes down to how lean the install is. For instance, if you install certain Intel drivers (WiFi/Ethernet/Bluetooth and such), they install themselves in 3-4 different directories, add useless icons to your control panel, etc. If you go with the one from Windows Update, the driver is a month or two older, but it has no fluff.
I always install the proper video drivers and chipset drivers. Everything else, I just roll with the Update drivers.