We will consider the feasibility of becoming a mount or pet.If you plan to make Dragons mountable, I'd suggest adding that feature to adult Dragons, which will give players a motivation to take care of them, like how Pokemon does
Try implementing the Pokemon system with this method, like making Biome Dragons obtainable at any point (so people wouldn't compare the dragons by appearance because of damage), both have same damage, but have unique attack types, and their damage are upgradable by token dropped by vanilla bosses, which their damage will be based on progression-tier (Forest Dragon with Moonlord-tier damage for example)
The reason why I suggest this is because I don't want to switch to different dragons every time I progress in the game, like I don't want to abandon Forest Dragon just because other dragons are stronger, if so, I'd like to maintain the appearance of the dragon, but make it useful for longer run at the same time
Dragons having their own different amounts of damage defeats the purpose of keeping them in your journey, and dancing along with them, basically just using them as a disposable damage dealer, and ditch them whenever you don't find the dragon useful, also making them easily forgettable with another better mounts and weapons from another mod
Similar to Pokemon, you can progress through the game with just Magikarp, because of it's leveling system, which helps you fight stronger enemies equally without having to ditch to another stronger pokemon
As for making a dragon mountable, add a saddle item the sold by town NPCs (Dryad or Merchant), equip it in dragon with its own UI, or simply use it as an accessory to make an adult dragon available for mounting
As for the weapons in other mods that make dragons easily replaced, this is not a problem we can control. After all, the process of many mods has been extended a lot, and the weapons will naturally be much stronger in the end.