You can check your saved posts and comments from your profile.

1. Open your profile screen.
2. Go to the saved section there.
3. Press the order button and select 'Show comments' to see comments.

You can also filter your saved content by community there.

That being said, this functionality should be added to the main 'Saved' menu too, as well as a search tool.

Perhaps a quick solution would be to separate the instance into a new line. Example:

Community name @instance

If it's an Android and using Gboard you can go to the symbol tab and hold - to choose the · symbol.