Could I be building my dogs stamina too much?

I have a 5 year old poodle who usually gets 2 walks a day, about 1.5 hours/6km minimum. It’s becoming colder here and so hour long walks are more difficult to do and will continue to become more difficult due to the snow. I feel like my dog also still has a lot of energy after walks, and doesn’t want to go home even after a 30-45 minutes one. She looks actually sad, energetic, and like I haven’t brought her out at all. I’ve been trying to play with her but she always ends up biting me and still has energy after (separate thing I’m trying to work on). Could I be setting myself up for failure by walking her so much?