This network has already been created, the coinjoin protocol you are referring to is called "WabiSabi"
As far as I know, WabiSabi doesn't have fidelity bonds. How does it defend against Sybil attacks? In a regular coinjoin, the coordinator must be relied upon not to orchestrate a Sybil attack. I reviewed your research paper, and it doesn't explicitly address Sybil attack protection; it only briefly mentions it in section 7.2.2.
Sybil attacks [Dou02] are an inherent threat to privacy in mixing scheme ...
A malicious coordinator may tag users by providing them with different issuer parameter ...
A malicious coordinator could also delay the processing of requests in order to learn more through timing and ordering leaks ...
Furthermore, service fees paid by honest participants may reduce the cost of such an attack or even make it profitable
Have they perhaps erred in using "profitable" here? It seems like "unprofitable" would make more sense in context.