What is this type of fixing? (similar to cam/dowel)
After more reasearch, it appears to be flat pack furniture assembly cam and dowel, more common on newer Ikea furniture. Try calling Ikea or checking online with them about replacement parts or extra parts. Or perhaps contact the manufacturer of the connector.

https://www.engineering.com/AdvancedManufacturing/ArticleID/11459/Better-Connectors-The-Future-of-Flatpack-Furniture.aspx

https://www.glaserbolt.com/torpedo/products