I like to use a mix of 3 mods for that:
-Animal Gear by Dylan
-Animal Equipment by Owlchemist
-Animal Gear Third-Party Patches by Samael Gray

Although the graphics for the armors are incompatible for the dragons, so when they wear it, it will visually not show on their sprites, however they do get the extra armor andinsulation from the apparel.

https://steamcommunity.com/sharedfiles/filedetails/?id=2971760258 this mod dosnt really have armor but it does have outfits