Alright, so you gotta understand why dragons are what they are. Check out this video but TLDR evolutionary biologists theorize that dragons are a composite monster of snakes, big cats, and birds of prey that arose out of humanity's ancient instinctual prey instincts. They're basically chimeras. (Which is probably why eagles were so easy for Tolkien to use.)
The thing about dragons is that they represent power. They are a terror. (Note: horror becomes horrific but terror becomes terrific; dragons can be benevolent or malevolent, but they must be impressive to be a dragon.)
If you want your dragon to be a dragon but also to make sense in its environment, then they won't be dragons - because dragons don't make sense in any environment. They're flying fire-breathing monsters. Whatever you choose, it doesn't have to be a flying bird or lizard so long as it's got that immense overwhelming power.
Look at Tamatoa from Moana - it's massive, nigh-unstoppable, self-important, obsessed with its hoard of treasure ... it's a dragon. But it's a giant crab. Not a flying lizard! Not a big bird! A giant crab. Check out his awesome song.
If your setting is taiga, cold forests, and steppe (like the Pontic-Caspian steppe bioregion?) then you need something that gives that same dragon emphasis but makes sense in context. Why not take creatures native to the Taiga and mash them together to make your own spin on a dragon? Like, the head and legs of a lynx on a slimy eel body. With elk or moose horns. And raptor's wings.
Or whatever! It's your fiction.
