Remove rewrite to eliminate 404s on existing subfolder

So I recently re-installed my WordPress site at:

https://mydomain.org

At that URL, I also had subfolders with non-Wordpress content like:

https://mydomain.org/subfolder1
https://mydomain.org/subfolder2
and
https://mydomain.org/subpage1.htm

etc.

Now that I’m running the latest version of WordPress at the above base path, it’s re-writing all of the URLS and returning the “This is somewhat embarrassing, isn’t it?” 404 error message when I browse to:

https://mydomain.org/subfolder1
https://mydomain.org/subfolder2
and
https://mydomain.org/subpage1.htm

I think this has to do with some .htaccess rewrite rule.

What I want WordPress to do is NOT REWRITE requests to /subfolder1 or /subfolder2 (these are non-Wordpress sites), just to ignore those requests and enable browsing to those folders.

Thanks in advance for your help!