Redirects with originating URL that has a "."

I’m trying to redirect from an originating URL like /about.html to my /about page in Softr. The 301 settings keep converting my originating URL to /about-html (with a hyphen). From what I can tell “.” is not equivalent to “-”

Note: There’s no way to change the originating URL to one without the .html – it’s preset.

Is there any way to get around this?

Where do you do this redirect?

Settings>SEO>URL redirects