I sold my old town of Carnival in 2016 to make Clover. I kept my catalog, so I immediately got the silver badge for the catalog from Phineas. It still took me ages to get the gold badge. Buckle up because this is a long ride. It isn't terrible if you don't mind waiting and break it into sections. Maybe collect all the K.K. songs first, for example, or all of the stationery. Then move to another category. Rinse, repeat. I'd recommend buying out the Able Sisters and Kicks shop supplies as well.
Congrats on getting the silver!
Thank you! Yeah currently in my town I always buy items from all the shops that I’m missing each day. I have an app that keeps track of my catalog (so for example, I can check if I have a certain item in Kicks already). It’s really helpful but at the same time, a little stressful cause I can also see how many items I still have to catalog haha