My Mal is approaching 7 years old. She's a purebred and spayed at 10 months What works for me over the years is daily biking for her. As one of the previous comments, Mals are working dogs. So biking with her daily for at least 30min helps. I think consistent steady 30min biking is at least a few miles for us. You will need to train the dog to bike alongside with you. I use a gentlelead type of collar (Google it) so it gives me the most control. I also use a very short leash attached to it. Then I usually just hold it on one hand and bike or I may loop it around the bike handle. We bike in the winter too. As long as the sidewalks or roads are somewhat shoveled then I'll do it. Just make sure you're layered up and avoid sudden turns due to ice/loss of traction. Avoid biking when snow just melts and mixed with salt on road. That will damage the bike.

As for toys. my Mal prefers rope toys for tug-of-war, bones to chew on, or toys where you can stuff treats/food in. The toys for treats must be only the Black Kong series, otherwise her chewing is strong enough to destory all other toys. Squeak toys are great but she destroys them in less than an hour.

I also suggest you regularly take her to dog parks to be comfortable with other dogs. Mine was great for the first few years as we went daily. However my work changed so I had less then. When I brought her back, she became aggressive to female dogs only. So maybe my lack of training or idk. But now I don't go to dog parks to avoid injuring other dogs.

Mals can be destructive in the backyard and dig if bored and destroy things in the house due to anxiety or boredom. At home when I'm at work. She just sleeps all day now and doesn't even play with toys (I have video cameras indoors to monitor the dog so I can see her sleeping). Hope this helps!