What banks will not use FedNow?

Could you elaborate on the banks that have decided not to adopt the FedNow service? Are there any specific reasons behind their decision, such as concerns over security, cost, or compatibility with their existing systems? Are there any notable banks that have publicly announced their intention to forgo using FedNow, and if so, what are their alternative plans for real-time payments? Additionally, what impact do you think this decision may have on the overall adoption and success of the FedNow system?