Basically an alternative to Rufus. Early in Win10's life Microsoft included a Windows To Go Creator in Control Panel, then later removed it. What Windows To Go is, is an external drive with 2 partitions, a small FAT32 partition for the boot loader [BCD], and a 2nd NTFS partition usually taking up the remainder of the drive space where Windows lives. Rather than installing Windows to that external drive, Windows DISM tool is used to apply an image. All the files for Windows are stored in a .wim file, which is similar to a special kind of Zip file -- Windows setup ISO contains a .wim file with the necessary Windows files, and both WinPE & the Recovery partition use .wim files containing a subset of the Windows files. SO when DISM applies an image what it's doing is copying all the necessary files in the correct folders so Windows will run. Because you skipped the full Windows installation, the 1st time a Windows To Go drive is run on new or different hardware, Windows checks to see what drivers are needed, then attempts to download and install them from Microsoft. That part doesn't always work. Windows may not accurately determine what drivers are needed, &/or Microsoft may not have them. There's also a potential problem where the drivers installed for one system, which are now installed in that copy of Windows, cause problems when you try to run that copy of Windows on different hardware. Ideally Windows will add drivers for the new PC/laptop, and not use any of the drivers added for previous hardware, but saying YMMV is a gross understatement.
You can use Windows BCDBoot to create the boot loader & DISM to apply an image from a Windows setup ISO yourself. or use RUFUS, WinToUSB Pro, AOMEI Partition Assistant etc. An app called ViVeTool will let you run several OSes from the same drive [Linux will run from an external drive too]. The original Windows tool required a setup ISO for Windows Enterprise -- I prefer to use the Enterprise version unactivated to avoid any potential activation issues.
WinToUSB Pro can also clone a copy of Windows to an external drive. You can do the same thing manually yourself, BUT, in my experience getting the boot loader to work can be hit or miss. One of the limitations running Windows on an external drive is that version updates that require a full (re)installation are not available -- Hasleo sells a companion app just to update Windows on an external drive for those situations.
And WinToUSB Pro can create a setup USB stick, same as Rufus, complete with bypassing Win11's hardware requirements.
WinToUSB Pro installs solely to the program's folder, and only needs to use one of the few registry keys it creates. Activation is tied to the PC/laptop hardware -- if activation works tomorrow you could conceivably use it portably.