Sleeping/ being tired too much?

I’m not sure if my 5 month old puppy is tired or bored or disinterested. Today he didn’t really seem interested in his walk, we walked maybe 20 minutes and he decided to lay down and just people watch. We live in an apartment complex so I took him to the garden so he can relax and I can sit next to him and he did the same thing. He just laid down even though I tried to play with him. He seemed to pull on the grass and chew on it. After a while,I had some of his treats with me and I had him sniff them out in the grass which he was doing since he’s very food motivated. Later in the day I tried again to take him out for a walk and I we ended up walking to the dog park. He played and he seemed to enjoy his time there.

Every time I try to get him to walk out of the apartment he makes it out of the door and just sits in the hallway so I’m not sure if he’s tired of his routine or bored of doing it consistently. He’s also been sleeping 8 hrs at night with 2-3 naps that last around 2 hours on my days off. He goes to daycare twice a day and stays with my parents 3 times a week since he can run around their yard while I work. On my days off we usually go on sniff walks every 2-3 hours and during meals I either train or have him sit and chase his food while I throw it. I’m not sure if I’m being boring with him or how else to add enrichment. I am planning to buy a flirt pole since he has a high prey drive and we’re going to see a trainer on Wednesday so hopefully I can be better for him. Any advice would be appreciated.