Windows explorer free space vs iPhone or iTunes reporting

For those of who still utilize a Windows PC with your iPhone, have you seen any reporting issues with WIndows Explorer?

In summary: When I connect my iPhone 8 via USB to my Win 10 PC, Windows Explorer is reporting as a warning I have less than 5GB free storage, although Windows iTunes reports more than 20GB free. Why is Windows Explorer reporting such a difference as opposed to the iPhone and ITunes?

In Detail:

I have an iPhone 8 with 64GB of memory -- 59.6 available to use. I'm a long time, old school user of iPhones with Windows PC and iTunes to manage. Besides plugging in to manage my music, I use the USB connection to open the DCIM folder and transfer the pics and videos off the phone.

When you USB plug onto Windows (Win10, current on software), a Windows Explorer (a.k.a. File Explorer) pops up to acknowledge the iPhone as "Internal Storage", and reports numerically and via a bar graph an indication of its recognition of total and free storage on the device.

Windows Explorer says I have less than 5GB free space out of 59.6GB, and the bar graph (typically blue when I plug in a normal external USB drive that is not near full), is red, inferring a warning situation. Beyond that warning, I am able to access and manage my DCIM folder.

Windows iTunes by comparison shows my device as having 22.2 GB free, and the iPhone itself (Settings) says I have 23.7 GB. There are many references online as to why iTunes vs the iPhone reporting differ, and they are relatively close, compared the Windows Explorer reporting of less than 5GB free. I've had no luck to date searching for any similar issues.

I called Apple Support yesterday, and they were stumped as well. I have an open case, and was referred to this community forum to post my question.

At the moment, I don't have any specific problem. However, I'd like to know because:

1) What would happen if I added say 6 GB of content, which is well within my free space? I suppose I could in fact do that to experiment, but I'd like to see if a shout out to this community can help first.

2) I'm technically curious as to why this is happening. I spent 33 years in IT and tech, and was quite the storage hawk when it came to systems management! ;0)