.htaccess.dist file by itself does nothing. Rename the file
.htaccess and eventually, your webserver will use it. This file is only used by apache web server. And even if you're using apache,
.htaccess files may be ignored. People should ask their webhoster, or check their apache documentation. That said, you don't need the
.htaccess file. This files tries to make sure that https is used for xmlrpc, but you can use xmlrpc without all that burden.
https://wiki.eotl.supply is already using https, and seems to be running under nginx, not apache. So unless you use nginx to proxy this web site requests to an apache worker, you can definitely ignore the
.htaccess file. nginx does not use .htaccess files.
Second, you don't have to set the remoteuser setting. but as @turnermm wrote, you should. With your current setting, everyone can use xmlrpc.
dokuwiki.getVersion should definitely give you an answer. see https://www.dokuwiki.org/devel:xmlrpc:clients#sample_curl_client.
Without code snippet and error code you get back, all I can tell from where I stand is that you have a problem with your webserver : Your nginx server sends a "500 internal error" when trying to run the
https://wiki.eotl.supply/lib/exe/xmlrpc.php using curl. You should check your nginx logs.