Netgear R6700v3 Readyshare doesn't see USB HDD when files are loaded onto drive

I've got a Netgear R6700v3 Nighthawk router, and having trouble getting the router to properly share the drive. I just picked up a Seagate Ironwolf 4 TB drive from Amazon so it should still be good. Wanting to do this to have network storage without too much hassle and expense of buying a NAS, plus I have a gaming laptop and there aren't enough USB ports on it to always have the drive attached. Did verify that I'm on the latest firmware version as well.

I put the drive in my external closure, the enclosure itself needs to be plugged in, doesn't draw from USB power so that's not the problem. Connected the drive directly to my PC (Windows 10), I formatted the drive to NTFS, verified that everything looked OK. I put a music file and short video on the drive, safely disconnected and connected to the router. Went into router settings to enable Readyshare, and could see the two files I put on the drive. I could play them no problem, and even tested out uploading files via the network to the drive. I do have a lot of files and wanted it to go faster, so I safely disconnected the drive from the router, connected it to my PC and put my files onto the drive. Now, some of them are large video files, movies and TV shows. Safely disconnect from computer, plug into router as before. Now when I go to the router settings it doesn't seem to see the drive anymore. I think at this point maybe it's because it's a large amount of files it has to go through them all, and as it was late at night I just left it on thinking it would get it done overnight. In the morning there's no change. I then safely disconnect then connect to my PC, and all my files are there in working order.

I've tried searching and the best I could come up with is only somewhat related. Apparently people were having problems uploading files over 4 GB through Readyshare, so could the problem be that having large files on the drive makes it unable to be read by Readyshare?