I have a Japanese futon mat[1] under my bed that I roll out if I have muscle soreness. If it weren’t for my partner (who insists on sleeping in a bed) I would sleep on the floor 100% of the time. After getting used to floor sleeping I can never feel truly relaxed in a bed-I feel like the padding is putting pressure on my lumbar spine.

[1] https://www.futonbedsfromjapan.com/