For strict brand compliance, I use Beautiful.ai. It preserves PPTX structure,...

https://mill-wiki.win/index.php/SlidesAI_vs_GenPPT:_Which_is_Better_for_Building_a_Deck_From_Scratch%3F

For strict brand compliance, I use Beautiful.ai. It preserves PPTX structure, avoiding those messy font substitutions after export