Abby
I'm a trainer and involved in rescue and in behavioral work, have two Rotties...we play training games, doggie-mind/puzzle games like these:
Nina Ottosson - Pet activity toys & treat puzzle games
and play ball - the youngest Rottie <the baby at about a year and 1/2> actually will play Fetch for about up to 45 minutes which is NOT a typical Rottie trait>
many years ago we pretty much emptied out the dining room since "entertaining' is not our thing and we don't have big families. We actually sold the sofas originally in there the first year or two we were in the house <before we got dogs> , and took the dining room table and chairs and another table down to the basement, and instead opened a large portion of that very large original "living/dining room" combo. We put the dog freezers in there, and dog crates, training equipment <I do agility, so we had a few small jumps and cavelettis in there> and dog storage chest and so now we have a space for the dogs to play and work in.
also, raw bones...don't use kibble at all, so the dogs can self-entertain by chewing on raw bones. The dog freezers are for the bones and dog food
hiding games are a lot of fun - have one person hold the dog and set yourself up away in a corner, behind something or just somewhere else in the room, have treats ready - call your dog, or clap your hands/leg, wave a cloth of flag, use whistle to get your dog to come to you - IF your dog has a Recall <dog, come> If not, work that. Work on tricks like "crawl", "sit up".....hide treats behind you and encourage the dog ti hunt for them - a natural behavior. Increase distance of treat-hiding til the treats can be in a corner across the room, or in another room, and the dog can find them. My girls both associate the verbal cue "Find" with "look for....something"
if able, run or move back and forth, calling your dog - a modified chasing game - dog learns, coming to you is fun, get treats. Increase the distance you move so that dog has to move farther to get to you.
Hide small bit of dry cold cereal, like plain Cheerios and that type of cereal or pieces of kibble, cut-up carrots in any of million types of dog food-hiding toys that are out there now, that the dog has to manipulate to get the food out of.
You can also use a clean, empty plastic milk or water jug with top and ring off, drop treats in there....make them able to come out, of course, but see if you can make it more challenging by making it so that the treats "just" can come out - dog has to expend more energy working at rolling jug, to get them out. This approach is more applicable to something you cut up yourself or maybe certain type of dry cereal, as opposed to Kibble.
Kongs- we have a ton of them....put applesauce, peanut butter, smushed banana, small bit of yogurt, add pieces of kibble, carrots, dribble of olive oil or canned fish to make it more smelly<dogs like "smelly"> - any food that safe for dogs - you can freeze them or put 'em in the fridge to harden up the contents and make it more challenging. We use raw meat in them also.
we also play Tug....
not all of this is going to work for everyone, just wanted to give an overview of ideas-