As a user of Pegasus under wine with Fedora 39 Linux at moment, some things I've found.
As has been stated the IERender uses calls that wine doesn't support, so normally the best thing is to use the uninstall program and completely remove IERender. Have also found that the 4.8x version have updated TER32 and HTS32. That do a pretty good job of supporting html emails.
I also added 94208 Mar 22  2022 TXML2.DLL that I found at the company site that makes the TER32 and HTS32. Not sure if it does more, but does seem to be accessed if there..
So, I also remove BEARHTML files as well. so it uses the TER32,HTS32, and TXML2 files.
Have a little issue with some Amazon messages that don't display correctly, but have a little script that can correct those.
#!/usr/bin/bash
sed -i 's</b> <br /> </p>=20</b><br /></p></td>_g' $1
Just pass it the cnm file name, and it cleans issue.
Also, have a more complex script that I use to allow options to open messages with the native 64 bit browsers of Linux rather than running one installed in wine.
/usr/bin/pegfire (sometimes using different browsers will display messages differently).
#!/bin/sh
input=$1
input1=${input:0:1};
link=$1
echo $1 $2 $3 $4 $5 $6 $7 >>/tmp/pegattach
xx=""
if [[ $input1 != "F" && $input1 != "H" && $input1 != "h" ]]; then
    link=https://duckduckgo.com/?q=\"$1+$2+$3+$4+$5+$6+$7\";
fi
if [ "$input1" = "F" ]; then
{
    link=$(echo "$link" |sed 's\/g;s_localhost'$HOME'_;s~C:/~.wine/drive_c/~'
    file=$(echo $link|cut -b 7-200| tr -d '\n' | tr -d '\r'
    sleep 1
    xx=$(grep "<html" <"$file"| tr -d '\n' |tr -d '\r'
    if [ -z "$xx" ] ; then
        filex=$file"L"
        echo "<html><body><PRE>" >$filex
        cat $file >>$filex
        echo "</PRE></body></html>">>$filex
        link=$link"L"
    fi
}
fi
Xdialog --radiolist "Browser to Use\n$1\n[$xx]\n" 30 160 6 \
    chromium-browser chromium-browser off\
    google-chrome google-chrome off\
    firefox firefox on\
    chromium-browser\ --incognito chromium-browser\ --incognito off\
    google-chrome\ --incognito google-chrome-incognito off\
    firefox\ --private-window firefox\ --private-window off\
    2>/tmp/browser 
retval=$?
browser=$(cat /tmp/browser)
if [ $retval -eq 255 ] ; then browser="firefox"; retval=0; fi;
app="";
case $retval in
  0)
    if [ "${browser:0:1}" = "c" ] || [ "${browser:0:1}" = "g" ] ; then 
        app=" --app=" 
    fi
    touch /tmp/pegattach
    chmod 666 /tmp/pegattach
    echo $link >>/tmp/pegattach
    echo     $browser $app$link >>/tmp/pegattach
    $browser $app$link;;
  1)
    echo "Cancel or Esc pressed.";;
  255)
    echo "Would have been timeout value pressed.";;
esac
Have to tell Pegasus to run that script for html files, and it does require xdialog to be installed.
I also use the wineHQ winehq-devel-9.2-1.1.x86_64 instead of the default fedora distro version of wine. 
Hope that helps.
 
        As a user of Pegasus under wine with Fedora 39 Linux at moment, some things I've found.
As has been stated the IERender uses calls that wine doesn't support, so normally the best thing is to use the uninstall program and completely remove IERender. Have also found that the 4.8x version have updated TER32 and HTS32. That do a pretty good job of supporting html emails.
I also added 94208 Mar 22  2022 TXML2.DLL that I found at the company site that makes the TER32 and HTS32. Not sure if it does more, but does seem to be accessed if there..
So, I also remove BEARHTML files as well. so it uses the TER32,HTS32, and TXML2 files.
Have a little issue with some Amazon messages that don't display correctly, but have a little script that can correct those.
\#!/usr/bin/bash
sed -i 's_</b> <br /> </p>=20_</b><br /></p></td>_g' $1
Just pass it the cnm file name, and it cleans issue.
Also, have a more complex script that I use to allow options to open messages with the native 64 bit browsers of Linux rather than running one installed in wine.
/usr/bin/pegfire (sometimes using different browsers will display messages differently).
\#!/bin/sh
input=$1
input1=${input:0:1};
link=$1
echo $1 $2 $3 $4 $5 $6 $7 >>/tmp/pegattach
xx=""
if [[ $input1 != "F" && $input1 != "H" && $input1 != "h" ]]; then
	link=https://duckduckgo.com/?q=\"$1+$2+$3+$4+$5+$6+$7\";
fi
if [ "$input1" = "F" ]; then
{
	link=$(echo "$link" |sed 's_\\_/_g;s_localhost_'$HOME'_;s~C:/~.wine/drive_c/~')
	file=$(echo $link|cut -b 7-200| tr -d '\n' | tr -d '\r')
    sleep 1
    xx=$(grep "<html" <"$file"| tr -d '\n' |tr -d '\r')
	if [ -z "$xx" ] ; then
		filex=$file"L"
		echo "<html><body><PRE>" >$filex
		cat $file >>$filex
		echo "</PRE></body></html>">>$filex
		link=$link"L"
	fi
}
fi
Xdialog --radiolist "Browser to Use\n$1\n[$xx]\n" 30 160 6 \
	chromium-browser chromium-browser off\
	google-chrome google-chrome off\
	firefox firefox on\
	chromium-browser\ --incognito chromium-browser\ --incognito off\
	google-chrome\ --incognito google-chrome-incognito off\
	firefox\ --private-window firefox\ --private-window off\
	2>/tmp/browser 
retval=$?
browser=$(cat /tmp/browser)
if [ $retval -eq 255 ] ; then browser="firefox"; retval=0; fi;
app="";
case $retval in
  0)
	if [ "${browser:0:1}" = "c" ] || [ "${browser:0:1}" = "g" ] ; then 
		app=" --app=" 
	fi
	touch /tmp/pegattach
	chmod 666 /tmp/pegattach
	echo $link >>/tmp/pegattach
	echo 	$browser $app$link >>/tmp/pegattach
	$browser $app$link;;
  1)
    echo "Cancel or Esc pressed.";;
  255)
    echo "Would have been timeout value pressed.";;
esac
Have to tell Pegasus to run that script for html files, and it does require xdialog to be installed.
I also use the wineHQ winehq-devel-9.2-1.1.x86_64 instead of the default fedora distro version of wine. 
Hope that helps.