I did that for dd1, blackout blinds for night sleep and naps. It was a bit of a mission for traveling, as we always had to take portable blackout blinds. She has grown out of it now though. She sleeps ok in the dark and with ordinary blinds too.
DD2 needs blackouts for night sleep, or else she’s up at the crack of dawn. Naps ok with ordinary blinds though. Every kid is different, you need to experiment and see what works.