There's a reason why essentially every single HL2RP server from 2016 onward stopped using jail sentences as punishment. Unless you have a staff member constantly GMing the prisoner's actions, or even a CP assigned for jailor duty, it's literally the same as just AFKing alone in your apartment, or even being temp PKed. Prison sentences kill RP, they don't create it. I experienced "prison" several times on HL2RP, and it's the same thing every single time: thrown in a small cell, AFK for 30 minutes, come out, continue as if nothing happened.
You shouldn't expect a jailed player to take initiative and start doing some epic prison break RP. You have to either supply them with roleplay by GMing, or improve on the system enough to make passiveRP viable. I should note that every single point in the OP only relates to implementing a cool new system for CPs and Dispatch; literally under 10% of the server's population.