Haven't tested this with the most recent Windows 11 installer but in the past what I do during the install is select that I'm setting the system up for a corporate / domain account. From there it allows to enter a normal Windows username/password like normal (you don't actually need a domain name but you can make one up if you want).
I use Linux, so I haven't run into this myself, but I assume that one can buy a copy of Windows 11 Pro separately from the PC itself, even if one doesn't currently have the Pro edition.
True, forgot all about the Pro/Home differences. Yet another reason to avoid Windows Home editions. To be fair OP didn't mention if they are on Windows 11 Home or Pro but perhaps you're right maybe they're on a Home edition.
Another comment mentioned Rufus which works well for Windows 11 Pro but I haven't tested it with a current Windows 11 Home installer so can't be sure how well it works for that.