KODI 21 Question about Startup Intro

New to coding for KODI but hoping to find some understanding....in Confluence 4713 for KOD19.5 (bc KODI21 is too buggy) i re-added Startup Intro option by adding: Startup.xml, SkinSettings.xml to 720p folder and Adding "Enable Startup Intro" to strings.po in languages folder. In order to have various custom intros for each Profile i changed the tag in "Startup.xml" to <onfocus>PlayMedia(special://profile/startup/,.mp4,1)</onfocus>. This allows any mp4 to be added to the "startup folder' in each Profile without having to rename them to intro.mp4.=WORKS PERFECTLY. **Now my question is...why doesn't this work the same in KODI21? ( i have already bonded these additions with Confluence 505 and all works fine...but ONLY if i change tag back to: startup/intro.mp4,1> and rename all startup video files to intro.mp4 as well)
<----------------------------Here's what I'm working with in Blue-------"Startup.xml"--------------------->
<?xml version="1.0" encoding="UTF-8"?>
<window>
    <defaultcontrol condition="Skin.HasSetting(Enable.StartupIntro)">10</defaultcontrol>
    <onload condition="System.HasAddon(plugin.video.themoviedb.helper)">Skin.SetBool(TMDbHelper.Service)</onload>
    <onload condition="!System.HasAddon(plugin.video.themoviedb.helper)">Skin.SetBool(Disable.NextAired)</onload>
    <onload condition="System.HasAddon(script.skin.info.service)">RunScript(script.skin.info.service)</onload>
    <onload condition="System.HasAddon(script.artistslideshow)">RunScript(script.artistslideshow,daemon=True)</onload>
    <onload condition="!Skin.HasSetting(Enable.StartupIntro)">ReplaceWindow($INFO[System.StartupWindow])</onload>
    <onunload condition="Skin.HasSetting(Enable.StartupIntro)">PlayerControl(Stop)</onunload>
    <controls>
        <control type="button" id="10">
            <include>HiddenObject</include>
            <onfocus>PlayMedia(special://profile/startup/intro.mp4,1)</onfocus>
            <onfocus>SetFocus(11)</onfocus>
            <animation effect="fade" end="100" time="100">Focus</animation>
        </control>
        <control type="button" id="11">
            <include>HiddenObject</include>
            <onup>ReplaceWindow($INFO[System.StartupWindow])</onup>
            <ondown>ReplaceWindow($INFO[System.StartupWindow])</ondown>
            <onleft>ReplaceWindow($INFO[System.StartupWindow])</onleft>
            <onright>ReplaceWindow($INFO[System.StartupWindow])</onright>
            <onclick>ReplaceWindow($INFO[System.StartupWindow])</onclick>
            <onfocus>ReplaceWindow($INFO[System.StartupWindow])</onfocus>
            <animation effect="fade" end="100" time="15000">Focus</animation>
        </control>
        <control type="group">
            <visible>Player.HasVideo</visible>
            <control type="image">
                <include>FullscreenDimensions</include>
                <texture>black.png</texture>
            </control>
            <control type="videowindow">
                <include>FullscreenDimensions</include>
            </control>
        </control>
    </controls>
</window>