Upgrade path: happy with my Gaggia but the grinder is holding me back?

Been running a Gaggia Classic Pro for about a year with a cheap conical burr grinder I’d rather not name. Lately I feel like I’ve hit a wall. Shots are inconsistent, I get a lot of channeling even with decent puck prep, and I can never quite dial in the fast-then-slow gushers. Everyone says grinder before machine, so I’m thinking that’s my upgrade rather than a new boiler. Torn between a DF64 for single dosing and a Eureka Mignon Specialita. I don’t switch beans daily so retention isn’t a dealbreaker, but I do like tinkering. For those who made this jump on a Classic, did a real grinder actually fix the consistency problems, or was I fooling myself? Budget is around $300.