Cannot make a multiboot USB with Windows

[Parted]

Hello everyone, I've been looking for quite sometime, but I haven't found the answer to my question. I bought myself a 64 GB USB 2.0 drive, because I wanted to make one flash drive for all I need. I use YUMI, but the situation is awful.

Basically I wanna put the following: Ubuntu 18.04, Hiren's Boot, Windows 7, Windows 10 on the flash drive, when I format it to FAT32, YUMI makes the whole drive in like 2 hours, but the problem is that Windows ISOs are 6 GB and the installer doesn't start (im doing x32 and x64 at the same time and after I choose Windows 10 64-bit, the installer returns an error, because FAT32 cannot handle files over 3-4 GB and the ISO is 6 GB). I tried using NTFS, but then YUMI will copy the 1 GB Ubuntu ISO for like 2 hours and a single Windows installer for like 15 hours..

Help please