When embedding image in the sitemaps, a problem occurs if you have medias relating to other medias. The problem occurs inside getEntityImageData where it keeps calling in the loop the function recursively.
I am embedding images in my sitemap and i have a field linking to a youtube video media. That media has a field named "field_related_videos" which links to other youtube video medias. That function keeps calling itself and the sitemap crashes.
A solution could be to either make some fields ignored, like maybe a configuration a field with a list of one field per line that would be ignored when crawling the medias.
Another solution could be to add a maximum depth in the recursion to prevent this kind of issue, but I think this solution is more a bandaid than a real fix.
Please open bug reports only against the dev version.
I feel like your second solution would be a good emergency break for these relatively rare set-ups. The first solution seems to require too much additional complexity.
Feel free to provide an MR and optionally a test for this.