Cloth diaper inserts? Helllp

Hello all - I am going to be cloth diapering my little guy, but I ordered our diapers with bamboo inserts and they seem so thin! I'm nervous they won't work well. They are very flimsy and don't seem very absorbent, even after multiple washes. I got them From Alva Baby. Anyone have experience with these? What do you think are the best inserts for these diapers, and where did you get them? I've heard flour sack towels work well also? Thank you! 💚