How to remove duplicate urls that are affecting my SEO - .htaccess

Question

Hoping someone can help me. I've tried everything I can think of and have spent almost 2 weeks now trying to solve this issue. I'm using SERanking for a site audit and it is indicating I need to fix the duplicate url issue.
Pages With Issues:
https://www.droneworxphotography.com/
0 (Referring Pages)
https://www.droneworxphotography.com/index.html
10 (Referring Pages)
https://www.droneworxphotography.com
10 (Referring Pages)
My htaccess:
RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.droneworxphotography.com/$1 [R,L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ /$1 [L,R] # <- for test, for prod use [L,R=301]
I've tried adding a 301 redirect, but it is not resolving my issue.
Redirect 301 /droneworxphotography.com/index.html /droneworxphotography.com
I'm hoping someone can help me with fixing this.
Thanks

Answer 1

As mentioned in comments, you need to actually fix your internal links so you are consistently linking to the canonical URL throughout your site, before attempting to implement redirects.
The "reported issues" you are seeing are presumably discovered by crawling your site.
As far as I can tell, my internal links are consistent.
Unfortunately not...
<!--begin footer_details -->
<ul class="footer_details">
<li>
<li> Redacted Photography
(Ignoring the incorrectly nested li elements - this is not valid HTML.)
You have a relative link to index.html in the footer of every page. This should be either, a root-relative URL (a single slash):
Redacted Photopgraphy
Or, an absolute URL (include the scheme + canonical hostname). For example:
Redacted Photopgraphy
Note the trailing slash after the hostname.
These two are the same. (Providing the hostname is correctly canonicalised before reaching your site. It appears to be - you have HTTP to HTTPS and non-www to www redirects in place.)
<!--begin logo -->
<img src="lib/images/cropped-DroneworxLogo_small.png" alt="Logo">
<!--end logo -->
<!--begin nav -->
<ul id="nav">
<li>
<i class="icon-home"></i><br>Home
You have 3 links on every page (the two above and one in the footer - copyright link) that links to scheme + hostname but without the trailing slash.
Strictly speaking, the "correct" URL includes the trailing slash after the hostname.
User-agents (ie. browsers) will correct this and always append the trailing slash, but you should be consistent and link to href="https://www.example.com/" - with a trailing slash. (Or use href="/" as mentioned above.)
Your XML sitemap already correctly links to the canonical absolute URL (with a trailing slash): <loc>https://www.example.com/</loc>
It is this inconsitency that is causing the SEO tool to report on both https://www.example.com/ (slash) and https://www.example.com (no slash). Although this is not really an SEO issue, since user-agents will always append the trailing slash to form a valid URL, as mentioned above. See my answer to the following question on the Webmasters Stack for more information about the trailing slash after the hostname: Is trailing slash automagically added on click of home page URL in browser?
Note that the trailing slash immediately after the hostname (at the start of the URL-path) is not the same thing as the trailing slash at the end of the URL-path.
Redirect to canonical
Once you have corrected the above then you can implement a redirect to correct any indexed URLs (or backlinks from external third parties).
The only redirect you could implement here is from /index.html to / (to remove index.html). You cannot redirect to append a trailing slash after the hostname (this is the same URL).
(Your mod_rewrite directives remove the trailing slash at the end of the URL-path - which is something different entirely. Your site does not have an issue with this, but this redirect causes no harm.)
To remove index.html you could add the following rule at the top of the .htaccess file, before your existing redirects (and after the RewriteEngine directive):
RewriteRule ^index\.html$ https://www.example.com/ [R=301,L]
NB: Test first with a 302 (temporary) redirect to avoid potential caching issues.
This does assume you aren't using a front-controller pattern (and rewriting requests to /index.html). It doesn't look like you are - your site looks like an entirely static HTML site?
A quick check in Google using a site: search does not show that index.html has been indexed. So, this was unlikely causing you an SEO issue at the current time.