Is there any way to use SVGs with Prismic at all? The blog post you refer to in the original answer only mentions the fact that SVGs are served as files from the CDN instead of the images.prismic domain as done previously. But, the served files are broken. The CDN serves a .webp file with an .svg ending essentially breaking any downstream decoding.
You can use SVGs safely. We made a change so that it didn’t compromise the security of the files since they are vulnerable to JS access. The only thing these files don't have is access to the Imgix integration, which allows for image optimization features.