I guess you can add properties/relations based on templates if that suits your flow better. When you open an object’s relations, it shows where the property is from, so it’s still segmented in some way. The ones that don’t apply can be left blank. If you want a property/relation to be enabled for all objects of that type, you can add it in the type itself. (Like Description)
Personally, what I do is create custom tags for what would be child types. So I can then filter it to that relation when creating a set. It does take some effort. Lately, I find myself using Collections more often so I don’t have to prepare a tag beforehand. (Whether you want a relation to show in your Graph or not is also something to consider.)
I believe types and relations (the library, in general) is still a work in progress. I’ve read posts before about having multi-types. You might be interested in this discussion:
This is exactly how you can do it, at present.
Also, you’re not alone in struggling with relations and terminologies, see here:
Feel free to add your thoughts and ideas as a way to vote and refine much needed feature requests.
