I just tried it in Firefox (latest/postmodern, Linux) and none (not a single one) of the form's fields are editable. It's an even worse experience than Libreoffice.
You can read more about PDF.js support for forms here.[0]
Libreoffice also supports creating Acrobat Forms.[1]
[0] https://blog.mozilla.org/attack-and-defense/2021/10/14/imple...
[1] https://www.linuxuprising.com/2019/02/how-to-create-fillable...
