if we are talking only about these columns - i think it's easy to do.
the code that makes these columns is:
<!-- *********************************** HEALTH ******************************************** -->
<rect pos="104,0" width="34" height="90" controller="HUDStatBar" stat_type="Health">
<sprite depth="1" height="36" width="90" sprite="stats_backgrnd" rotation="90" color="255,255,255,180"/>
<sprite depth="2" name="background" height="36" width="90" sprite="stats_backgrnd" type="filled" fill="{statmodifiedmax}" rotation="90" color="255,255,255,240"/>
<sprite depth="3" name="BarContent" pos="2,0" height="32" width="90" sprite="health_bar" type="filled" fill="0" rotation="90" globalopacity="false"/>
<sprite depth="4" name="Icon" pos="-2,26" size="40,30" sprite="health_pad" foregroundlayer="true"/>
</rect>
<!-- *********************************** STAMINA ******************************************** -->
<rect pos="156,0" width="34" height="90" controller="HUDStatBar" stat_type="Stamina">
<sprite depth="1" height="36" width="90" sprite="stats_backgrnd" rotation="90" color="255,255,255,180"/>
<sprite depth="2" name="background" height="36" width="90" sprite="stats_backgrnd" type="filled" fill="{statmodifiedmax}" rotation="90" color="255,255,255,240"/>
<sprite depth="3" name="BarContent" pos="2,0" height="32" width="90" sprite="stamina_bar" type="filled" fill="0" rotation="90" globalopacity="false"/>
<sprite depth="4" name="Icon" pos="-2,26" size="40,30" sprite="stamina_pad" foregroundlayer="true"/>
</rect>
<!-- *********************************** FOOD ******************************************** -->
<rect pos="0,0" width="34" height="90" controller="HUDStatBar" stat_type="Food">
<sprite depth="1" height="36" width="90" sprite="stats_backgrnd" rotation="90" color="255,255,255,180"/>
<sprite depth="2" name="background" height="36" width="90" sprite="stats_backgrnd" type="filled" fill="{statmodifiedmax}" rotation="90" color="255,255,255,240"/>
<sprite depth="3" name="BarContent" pos="2,0" height="32" width="90" sprite="food_bar" type="filled" fill="0" rotation="90" globalopacity="false"/>
<sprite depth="4" name="Icon" pos="-2,26" size="40,30" sprite="food_pad" foregroundlayer="true"/>
</rect>
<!-- *********************************** WATER ******************************************** -->
<rect pos="52,0" width="34" height="90" controller="HUDStatBar" stat_type="Water">
<sprite depth="1" height="36" width="90" sprite="stats_backgrnd" rotation="90" color="255,255,255,180"/>
<sprite depth="2" name="background" height="36" width="90" sprite="stats_backgrnd" type="filled" fill="{statmodifiedmax}" rotation="90" color="255,255,255,240"/>
<sprite depth="3" name="BarContent" pos="2,0" height="32" width="90" sprite="water_bar" type="filled" fill="0" rotation="90" globalopacity="false"/>
<sprite depth="4" name="Icon" pos="-2,26" size="40,30" sprite="water_pad" foregroundlayer="true"/>
</rect>
regarding how to insert it into the vanilla code - hmmm.... i'll pass. Don't ask me to do something for vanilla - i haven't been there since 2015y

. (i can only tell - that it definitely does not require .dll edits, and it does not require any other tricky manipulations with the rest of the code)
In addition - i absolutely do not know how to make these "modlets"...
Ps: of course, this will require the appropriate sprites (by name) in the appropriate directory (mods folder ???).
(please - i can help with any consultation, just not about vanilla...)