How to keep baby entertained?

My baby is almost 5 weeks old, and spending more time awake. But, I am not sure what to do to keep him entertained. We do tummy time, but not for long,as he gets fussy, I've held him under him arms while his feet touch ground or my legs, but I can't do that forever. I've read to him,but usually lay him down in my arms to do that, and he doesn't like that. He is to the point that if he isn't eating or sleeping, he doesn't want to be laying down, not even in my arms. FTM here, so just not sure what to do to entertain him since he is still so young.

Yes, we've gone on walks, but that is more for me since he falls asleep every time 😅