[Samsung Galaxy Tab S8] drjoe1:
For the fun of it (I know, I have a weird idea of fun), a little background on what we are talking about... I think lots of people don't know the difference between 32bit and 64bit, or what FAT32, exFAT and NTFS are!

FAT32, exFAT and NTFS are all different Microsoft file systems used to encode data storage devices like hard drives, flash drives, and SD cards. Apple has two of its own. Most storage hardware not purchased directly from Apple is formatted out of the box with a Microsoft file system.

FAT32, "File Alocation Table 32" is a 32 bit system that is older and went into the public domain some time ago -- companies can use it without paying Microsoft royalties. But because it is 32bit (32 bit = the length of the "words" it can use), The size of 32bit is 2^32 values, or 4,294,967,296 -- that is 4GB! So It limits file sizes to 4GB,and storage to 8TB. But it is free so many hardware developers use it.

NTFS, "NT File System" was developed by Microsoft back in the 90's for hard drives to more flexibly save data -- it is variable between 32bit and 64bit, so no file size limitations (well, effectively - the limit is one petabyte or 1 Million GB. I haven't heard of video files this big - YET!). The length of the "words" is exponentially larger for 64bit compared to 32bit. 64bit = 2^64 values, or a 18,446,744,073,709,551,616.

exFAT, "Extended File Allocation Table" is a 64bit version of FAT32 that is optimized for flash drives, SD memory cards, and the like. It has the same file size limit as NTFS. If you buy a USB flash drive or memory card, it is probably formatted as exFAT. It became public domain only in 2019. Before that you had to pay royalties to Microsoft to use it. So it wasn't built in to as many things as FAT32.

SO.... The Android file system was built supporting FAT32 and not exFAT or NTFS. You could download large files greater than 4GB (in my experience, mostly hi-def movies / video files or game roms used with emulators), but you couldn't manually move them on or off the Android device using Android file managers. Also, you couldn't mount storage devices that were formatted in exFAT or NTFS. Because the developers at Google didn't want to pay royalties to Microsoft.

So all the hacks I listed above came into play. A few App developers like Paragon and NeatBytes (developer of Solid Explorer) paid Microsoft for a license to support NTFS and exFAT. Now that exFAT has gone into the public domain rumors are that Android 13 and above contains/will contain support for exFAT.

This is why the OP's question was weird:

1) You can't (out of the box) mount exFAT on Android

2) You can't copy 4G files to FAT32 (which you _can_ mount)

3) You can't download directly from the internet to an external drive bypassing internal storage (both the primary memory or the expansion SD card)

He wanted to do 1 & 3 above at the same time.

Here are some links for more info

On FAT32, exFAT and NTFS:

FAT32 vs. exFAT vs. NTFS: What's the Difference?

Not sure which format to go with?

www.howtogeek.com

On 32bit vs 64bit:

What Does 64-Bit And 32-Bit Mean For Your Computer? | Next7 IT

What does 64 bit mean and how can it affect your computer? Learn more about 32- and 64-bit operating systems.

www.next7it.com

On Microsoft's Licenses for FAT32 and exFAT and Android Support:

The patents on FAT32 are now fully expired, including the final lingering LongFi... | Hacker News

news.ycombinator.com

Tech Licensing Programs: exFAT and more | Microsoft Legal

Discover technology licensing programs for OEMs and developers from Microsoft Legal. Learn more about programs like exFAT, EAS, and Azure RTOS and how they help businesses.

www.microsoft.com

Android 13 will get official support for exFAT after years of development hell

A very subtle change allowed a Pixel 6 Pro to read an exFAT-formatted drive, but it took a lot to get there

www.androidpolice.com

later,

Joe