I would like to suggest Ventoy for the sake of convenience. You can just copy the bootable images (iso, efi, …) to the drive and boot selectively using the menu. Been using it couple of years, and its a pretty nice solution.
Of course, depending upon where you acquire a package, any software could be considered malware. Always download from the original site, or one that is trusted; that’s a simple strategy to follow to avoid malware.
On topic:-
Balena Etcher is a valid tool for your needs; and is available for major platforms.
Note:- The AUR version seems to be broken currently.
PS: Ventoy is still a great choice. You only need to write Ventoy to the USB once (unless you want to update it). Then place whichever ISOs you wish to boot from in the respective folder.
I just tried it and it does load the Windows ISO but it will not.install windows because it says it can’t find the drivers. All of the stores are closed… Can’t buy any blank DVDs.
I tried both Balena / Belana Etcher program and the USB does not boot… I tried with that vanoy program and the windiws installer will not detect the drivers to.install windows…
This makes no obvious sense. If the Windows ISO boots, you just need to follow the prompts to install it. If you find an error during Windows installation, that is certainly not a Manjaro issue.
May I suggest Microsoft may be a better forum to seek information.
Here are two possible procedures found with a simple Google search. I hope these are useful, however, these guides are neither recommended nor endorsed. Good luck.