My cat is getting bored because he doesn't play with toys alone

Context- I have a 2 year old Indian stray. He's extremely docile and obedient. But he has a weird habit that he only plays with his toys when someone is playing with him, never by himself. We've gotten him motion activated toys and hung string toys, hoping he would entertain himself when no one is home but he just meows and gets distressed due to boredom when left alone. Since we're all working in my family, it's difficult to entertain him during the day which is slowly leading to him being chronically bored and I'm worried it'll depress him. Any suggestions on how I can encourage individual play in him? He doesn't even knock things over or tear papers which is great as he's 'low maintenance' but we're slowly realising that maybe he's low curiosity? Any suggestions?