How can I tire out my dog in the winter?

I recently adopted my dog around June and she’s been pretty easy to exercise and tire out before it got very cold. She’s about 2 years old and after doing a dna test, she’s mostly apbt/gsd. We walk every morning, mostly allowing her to sniff but doing a little bit of training outside as well. We train inside and play before I go to work. She also spends the whole day with a rover sitter twice a week. We train daily and I try to take her to a new location for a hike at least once a week. I also have used slow feeders, kongs, and lick mats. Really just looking for a way to continue to keep her fulfilled as we live in a one bedroom apartment in a city. She is my first dog and although I think I’m doing very well considering, I’m curious what I can do to keep her more fulfilled as I realize others have more experience than I do. Looking for any tips and tricks, thanks!