Can't find Cherubi? Not on the Routes or in the Wild? It's normal, this one simply hides in the Berry Trees!
The Berry Trees
In Pokémon Sword and Shield, you will have noticed many fruit bearing trees. These are berry trees. By shaking them, you can not only reap the precious fruits but also come across a wild Pokémon. Most often it is a Skwovet, but sometimes you may come across Cherubi.
For that it's very simple: by shaking the berry tree, don't hesitate to continue until a shadow falls on you. On the other hand, if you want to avoid wild Pokémon, click on "Stop" and you can get your berries back.
Most Berry Trees are found in the Wild Area and fill with new fruit daily. The chance of finding a Cherubi in the Wild Area trees is 5%.
But the Galar Routes sometimes also have Berry Trees.
Nothing confirmed at this time, but it seems that the Berry Tree of Route 3 maximizes the chances of encountering a Cherubi.
Last solution: it's possible to find Cherubi and its evolution in the Max Raid Battle.