Server-side tracking solves signal loss. It does not solve a measurement model that was wrong before the signal ever left the browser. Those are different problems and they get conflated in almost every pitch we see.
“If your event taxonomy is wrong, server-side delivers the same wrong events with a better delivery rate.”
Fix the taxonomy first. Agree what a conversion is, in one sentence, with finance in the room. Then move it server-side and enjoy the improved fidelity of a number that now means something.