If you're just going to the link to visit it yourself, that's the proper link. If it wasn't a lemmy.ca link you wouldn't be able to interact with anything.

But when you're sharing communities, (like linking them in posts), you should use !community@instance (e.g. !fossdroid@social.fossware.space).

This is done so anyone from any instance can go to the community and interact with it, instead of being sent to lemmy.ca where they won't be able to interact.

If you're linking to a community outside of Lemmy, what's usually done is to link to the instance the community's in (e.g. https://social.fossware.space/c/fossdroid)

You should be able to see the ! link for most communities under the title, and you can right click copy it to get the link to the community in its home instance.