I'm completely out of the loop on this new Coinbase Blockchain

I've read a couple articles and watched a couple videos but I'm still completely in the dark and confused. Can someone do a quick ELI5 for me and I imagine others as well? Here's what I'm wondering...

Just overall what is it?

Is this chain specifically for Coinbase and Coinbase products or is it something for the wider crypto space?

I assume its its own chain ie not run on Ethereum. How does one interact with the chain, especially considering from my understanding it doesnt have its own coin?

What is the purpose, what are we going to do on there?

If it doesnt have its own coin how do we get funds on there ie can we use say Ethereum or Bitcoin on there?

How to get involved early and potentially profit later on?

Can someone school me on what this new Coinbase Blockchain is? Also is it something r/cryptocurrency and the crypto community in general hate because coinbase is behind it?