If I had to guess based on my understanding of attachment theory, it could be the anxious attachment, the avoidant, or the disorganized (which has traits of both, and is rare). In any case it’s clearly the insecure attachment styles.
Based on the “incel” description itself though, I don’t think you have enough information to guess either. An individual hokkikomori is clearly more avoidant than anything though, as they don’t seek or hold relationships with others as valuable.