I've been experiencing really slow boot times (~1 minutes sitting at EVGA splash screen with A2 at the bottom). Whereas about a month or so ago, I was getting logged into Windows within 10-15 seconds. On the flip side, my computer is also taking awhile to shut down, from 5ish seconds to shut down to upwards of 20-30 seconds now. I had 1 lucky boot where it was back to normal today and now it's in the same old slow boot and shutdown.

Specs:
i7-8700k @ 5.0GHz
EVGA Z370 FTW, BIOS v1.10 (also happened on v1.09)
MSI 1080ti GTX DUKE OC
G.Skill - Ripjaw V 16 GB @ 3200MHZ C14
Two SSDs (Samsung 850 EVO 1 TB and ADATA 1 TB)
 
These issues started around when I installed 6 LL120 fans and I had to get a NZXT internal hub with multiple USB2.0 splitters so I could sync my pump (Corsair H100 v2) and the LL120s.
I've unplugged it and I'm still experiencing issues and I'm not sure what could be some causes? It seems that something with the boot process (devices, drives, etc.) is not working and I'm not sure what the best approach to diagnosis this issue as.

Yes that is the fan kit. With everything completely disconnected from all USB2.0 hubs.

Prior to my LL120 fans, I had my pump connected to the USB2.0 hubs, boots fine. I had the lightning node (RGB controller) connected to the USB2.0 hubs and pump disconnected, booted fine. Then I got the NZXT internal USB2.0 hub but I needed to get a molex power cable for my PSU so I had it plugged in to the USB2.0 header just no power and recently I installed the molex power cable and got everything synced up, pump and RGB controller into NZXT internal hub and then the internal hub plugged into USB2.0 on mobo.
 
I'm not sure when these boot issues started within that timeline... I suspect it was when I got the NZXT internal hub powered up and going but even with that disconnected, it's still loading slowly.

GGTV-Jon
Save your OC information then shut down. With the NZXT hooked up clear the CMOS, reboot and load optimized settings - see if it behaves normally then. If boot and shutdown is then normal go over the difference between the optimized settings and your OC settings. Perhaps with the addition of the NZXT hub and the other controller it needed to do a reset

The BIOS was reset with me updating to v1.10 (yesterday). I just did a hard CMOS reset via the back switch and nothing has changed. Still slowly booting in.

GGTV-Jon
In the memory section is there an Relearn / Train option that is selected?
That would cause an extended boot, but wouldn't affect shutdown

No setting that I see relating to that. I've only adjusted memory to XMP 1 with 1.35v. I'm not sure if any settings in BIOS might be doing this since I've ran the same/similar settings the entire time but could be different now I have the NZXT internal hub installed. Is this possibly related to a driver for one of my devices such as mouse or keyboard or possibly an SSD issue not being recognized or delaying the booting process?

Last BIOS time was ~12 seconds (sounds normal with my usual 15ish second boot time)... I just noticed something while looking through my device managers that my 2nd SSD is not being detected (didn't have anything on it) but that might be the issue that is slowly things down? It's also not showing up anymore in my Disk Management so I'm not entirely sure what happened.

Going to go into the case to take a look.

EDIT: Unplugged my 2nd SSD and it boots normally now.. looks like it was an issue with it. Wondering if this is something related to the internal hub messing around with the SATA ports on the mobo?

lonkev maybe see if you can pick up an Samsung M.2 NVME drive with an comparable drive size or bigger then your current OS drive - use the Samsung software to migrate the OS install over too it.
 
Then wipe your current drive and use that as a secondary drive