Remove file association for folders

You can change the association of an extension using RCDefaultApp. However, it is no longer supported & in the past year the original site has vanished. It was already ancient, but has worked since about 2004 without change.
It does still work for certain in Mojave, possibly Catalina, but as far as I'm aware, not Big Sur.

You can get it from file sites like CNet, MacUpdate, Softpedia etc

There's a modern replacement for RCDefaultApp called SwiftDefaultApps but it doesn't do Extensions.

tbh, your choice of extension was unfortunate. Macs reserve certain extensions to make into virtual packages; Logic is one of them. It doesn't rely on you having the app installed, it's right down at system level, as a known extension. In effect it's the same as calling a folder company.project.app or company.project.zip & wondering why it misbehaves.

As a workaround you could right-click > Show Package Contents, but you'd have to do this every time.