The ability to generate payload xml for titles available via addons will depend on the addon. You mention Genesis. If I'm understanding their documentation correctly, it seems as though Genesis allows users to integrate all their titles to Kodi's TV database and Movies database.
https://seo-michael.co.uk/how-to-integrate-genesis-with-xbmc-library/If that is really the case and you have done that, then I think you could simply generate your TV and Movie payload xml files the usual way, and these files should contain the Genesis data. (I'm not sure though.)
In general, the addon media data is not stored in Kodi's databases -- just the basic settings or info about which addons a user has installed. The media data is usually located externally, somewhere online.
In the case of the user who's relying on the 1channel search, he is using payload dictation. This is a reasonable option for native speakers who are using VoxCommando (not VoxCommandoSP) depending on your microphone setup.
The caveat regarding loading large payload XML files is worth keeping in mind, depending on the size of an addon's database (see the wiki page on loading payload XML for
large music libraries).
For any addon that has a website or online database that users can scrape, it's usually not too hard to use a scrape action and some basic regular expressions to generate the relevant payload xml.
Or, you could scrape any site online to generate your list, with the risk that your addon may not contain all of those titles.
For example, I can easily create a payloadXML of 1900 TV series titles using this imdb page:
http://www.imdb.com/list/ls051178000/Here is the command:
<?xml version="1.0" encoding="utf-16"?>
<!--VoxCommando 2.1.4.2-->
<command id="592" name="scrape TV series" enabled="true" alwaysOn="False" confirm="False" requiredConfidence="0" loop="False" loopDelay="0" loopMax="0" description="">
<action>
<cmdType>PayloadXML.Clear</cmdType>
<params>
<param>payloads\TopTV.xml</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>Scrape</cmdType>
<params>
<param>http://www.imdb.com/list/ls051178000/</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>Tools.Unescape</cmdType>
<params />
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>RegExTool.Open</cmdType>
<params>
<param>True</param>
</params>
<cmdRepeat>0</cmdRepeat>
</action>
<action>
<cmdType>Results.RegEx</cmdType>
<params>
<param>src='/rg/item-title/list/images/.*?href="/title/.*?>(.*?)</a></param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>Results.MatchToXML</cmdType>
<params>
<param>payloads\TopTV.xml</param>
<param />
<param>True</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<phrase>scrape TV series</phrase>
</command>
The same basic premise would apply to scraping data for a particular addon's database, if they make that data accessible somehow.