Check Ventoy https://www.ventoy.net/, it supports ISO, virtual hard drive, etc. with just copying the files. For example you have a windows ISO you just downloaded, you can directly copy the file like normally.
Use their installer, specify your boot mode to legacy/UEFI and your partition table to mbr/gpt, optionally specify the size so you can keep storing other files. My configuration is UEFI and GPT which works on modern computers. I left a 4gb partition for files like software I use after installing the OS.