Hi @Loic1,
I recommend trying the Alternative HTML Article Galley Plugin (if you haven’t already), available here: Release OJS 3.2 · ajnyga/embedHtmlArticleGalley · GitHub
The functionality for this plugin is described here: Allow inline presentation of HTML Galleys · Issue #6279 · pkp/pkp-lib · GitHub
I hope this allows for you to display the HTML in the way you are hoping, but please let me know if it does not, and there may be another answer or an opportunity to suggest a feature request.
Best regards,
Kate
PKP Publishing Support Specialist