Struggling with ZZ Plant — would appreciate advice

I want to be honest: I'm not getting great results with ZZ Plant and I'm not entirely sure why. leggy growth reaching toward insufficient light has been a recurring problem despite my attempts to address it. I've been focusing on wiping dusty leaves with a damp cloth to improve light absorption based on everything I've read.

air-purifying properties in enclosed indoor spaces is there in glimpses, which tells me the plant has potential in my conditions. I have it in a bright indirect windowsill away from heating vents which might not be ideal. growth spurt when longer days arrive in spring showed some improvement. Two stars for now — not the plant's fault, but not a success yet. I'll update if things improve.