You can use Ventoy to have multiple ISOs in a single USB drive. When creating a new USB, make sure to enable Secure boot from Options. If there is a problem booting in or there is a weird blue screen, read this or search for Ventoy Secure Boot in UEFI mode.
My current setup (on a 16 GB thumbdrive)
- Hiren’s BootCD PE (~1.2 GB)
- MemTest86 (~512 KB)
- Fedora 36 x64 Live ISO (~2 GB)
- Windows 10 21H2 x32 Spanish_Mexico (~3.7 GB)
- Windows 10 21H2 x64 English_International (~5.6 GB)
You can download Windows 10 ISOs from tb.rg-adguard.net.