Leveraging lookbehind regex to protect text in xml file

I am trying to use a look behind to protect a parameter in an xml file. When I try to add the regex to the embedded content processing, nothing changes for the file filtering. I want to protect the entire parameter value as it is not to be translated and we've run into issues when it is fully exposed. I am looking for ideas for how I can leverage the xml filter while protecting these parameters from translation.

Regex:

(?<=[\n\s>])(\w+?<sub>.+?<\/sub>?)

Example text to be converted to inline placeholder:

t<sub>PLMT</sub>   -->   {1}

Sample xml:

Fullscreen
1
2
3
4
5
6
7
8
9
<section id="SECTION" ishcondition="legacy=filter3">
<p id="GUID">The period of internal pulse generator
(t<sub>PLMT</sub>) is set by the C<sub>PLMT</sub> capacitor. The period,
t<sub>PLMT</sub> defines the minimum repetition rate of LED current pulses
allowed based on external UDIM signal and is set based on the maximum PWM frequency,
f<sub>PWM(MAX)</sub>. An additional margin in design is necessary to compensate
for the component tolerances and noise in the system. The t<sub>PLMT</sub> period is
determined using <xref href="GUID" />.</p>
</section>
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

<section id="SECTION" ishcondition="legacy=filter3">
<p id="GUID">The period of internal pulse generator
(t<sub>PLMT</sub>) is set by the C<sub>PLMT</sub> capacitor. The period,
t<sub>PLMT</sub> defines the minimum repetition rate of LED current pulses
allowed based on external UDIM signal and is set based on the maximum PWM frequency,
f<sub>PWM(MAX)</sub>. An additional margin in design is necessary to compensate
for the component tolerances and noise in the system. The t<sub>PLMT</sub> period is
determined using <xref href="GUID" />.</p>
</section>

emoji