I'm stupid and i want to learn

I'm very embarrassed to make this post.

I don't understand how tokens built on top of other ecosystems work and i don't understand how the parent system benefits from this.

For example Ethereum- on the Eth network there are many tokens and DApps. So if Matic runs a swap or defi app and all the fees are paid in Matic tokens how does this help or support eth? Does it effect eth at all? If not then why does eth have any value shouldn't everyone be investing in the DApp tokens?

Something that seems similar to me is Terra system Luna and Anchor protocol. When I read about it, it days Luna is the engine everything runs on but Anchor protocol has its own fees and they are paid in their own tokens so what does Luna actually do here? Sure they made the code that Anchor runs on but do the Luna tokens do anything? Do any fees go back to Luna?

Idk how you guys learn this stuff, I'd like to find more educational sources.