Exactly as title states. This was tested several different times with Gobber 2. Despite correct formatting according to the wiki, the new forge would not appear. However, with Gobber 2's Fabric port, the aforementioned forge would be added in with little issue.

With Gobber 2's Forge Port:

With Gobber 2's Fabric Port:

Moddata Directory (/moddata/custom_content/alloy_forges):

(New forges appear incomplete due to WIP texturing)

I managed to fix the item's textures issue by making a resource pack with the textures required by the custom forge

(the resource pack in question)

However, the block's textures when the item is placed are still broken, I'll let you know if I'm able to fix it

EDIT: I fixed it! There were just some problems in the file names

For new forges to have a texture, you need to include the following files in a resource pack

(in this example, it's for a netherite block forge, change the file names and their contents to match the name of your custom forge)

I still haven't fixed the name though, but the functionality works fine. This could be a good workaround until they fix connnector compatibility