Three years at a service company and every product interview asks why my work sounds so generic

Most of what I've done is maintenance on a client's codebase, tickets scoped by someone else, no say in any of it. Product companies keep asking what I owned and I don't have a clean answer. Has anyone actually made this jump? Did you have to build side projects to prove you can think past a ticket, or is there a way to frame client work that doesn't sound like I just followed instructions for three years?