You have probably already thought about this, but Ragna is probably becoming a dragon, with Artemisia's Time-Stop registering him being in the state of maturation and partially allowing him to move (of course, a little later he forces his way in with the nullification of the silver aura), and thanks to Taratectora we know that the time someone spends in the maturation stage is defined by their talent, which made Taratectora take twenty years to leave the maturation stage, and we know Ragna's position in relation to talent, so if he is really becoming a dragon, it will take "just a little while" for him to become one