Grinder burrs dulling seem like they would be a slow process under home use, not a "few weeks" kind of thing. As I recall, the Rossi RR-45 uses 64 mm burrs, so they probably last "years" under home use. The similar-size Mazzer Super Jolly burrs are said to have a 440 kg expected life. At 1 kg/month, that's decades.

Wet pucks, by themselves, aren't an issue. That things are different suggests that the way the extraction is proceeding near the end of the shot is different.

I'd try a couple things to try to narrow things down.

Deep clean the grinder. I'd use some brushes and a vacuum cleaner. Use a vacuum cleaner that is small enough so that when you discover you've sucked up something small and important, going through the bag won't be a terrible task. Try to keep grinds and dirt out of the body and collar threads. I'm not a fan of Grindz or rice for a variety of reasons.

Try a different coffee. Coffee is an agricultural product, that is then often hand processed. Every batch is a little different. Sometimes a lot different. The better blender/roasters do a good job of keeping it reasonably consistent batch after batch by varying the blend and roast profile over time, but there are still differences.