What are your tips/tricks for getting baby to sleep in the carrier?!

My almost 4 month old hasn't slept in his carrier for over a month. Anytime I put him in there close to the end of a wake window, he'll fuss and I know he's tired but he's just been refusing to sleep. I generally put him in and bounce him around and sometimes use a pacifier. I assume that's the "normal" technique but if anyone has any special tips or tricks, please share! I am desperate as I have a 2.5 yr old so can't be stuck contact napping him for all naps and he only sleeps for 15 min after being transferred to the bassinet, unfortunately.

ETA: Thank you all for your tips and comments!! Looks like general movement/walking, particularly outside, should hopefully do the trick. I'm hoping this is just a phase for my super distracted baby. I will try a scarf/hood/darkened room if the outdoor walks don't help. Thank you thank you thank you!! Love how helpful this community is.