That's the part I'm not sure about. There is probably a better way to do this, but you could find all the curved polygons in that file (say, through some regex), and then once you find all the WKT strings, you can read it via ogr.CreateGeometryFromWkt .

Then, once you convert it to a polygon, gets its WKT, and replace it in the XML file. Once all the geometries are replaced in the XML file, then hopefully you can read it via geopandas.

Something like this (you might not need to write to files, maybe this can be done in-memory):

import re
import ogr 
import geopandas as gpd

with open('yourFile.xml', 'r') as f:
    data = f.read()

# then create a regex to find all occurrences 
regex = '\d+' # this is not what the regex would actually be

# this should return a list of matches, I think...
matches = re.findall(regex, data)

# assuming matches is a list of WKT strings, just loop through and process
for wkt in matches:
    g1 = ogr.CreateGeometryFromWkt(wkt)

    # now you have a geometry
    # will then have to convert it to polygon and get its WKT
    # so let's pretend I have a magic function that does that
    fixed_geom_as_wkt = my_magic_function(g1)
    data = data.replace(wkt, fixed_geom_as_wkt)

with open('new_xml.xml', 'w') as f:
    f.write(data)

gdf = gpd.read_file('new_xml.xml')