Big Sur won't open SeaMonkey--alternative WYSIWYG Web page editor for the barely amateur?

I have long used SeaMonkey to create my totally plain web pages for
my web site--mostly recipes, primarily text and sometimes a few
photos. Big Sur is refusing to open it because 'developer cannot be
verified' or something like that.  I like the WYSIWYG because it's
almost as easy as MS Word.

Can anyone suggest a better option that will keep Big Sur happy, and
let me do very simple web page edits?