Are cosmos and polkadot similar?

I've been following the development of cryptocurrencies closely, and I've noticed that Cosmos and Polkadot seem to share some similarities. Could you elaborate on their commonalities and differences? For instance, do they both aim to solve scalability issues in the blockchain space? How do their interoperability solutions compare? Also, I'm curious about their respective ecosystems and the types of projects that are building on these platforms. Could you provide some insights into that? Understanding these aspects would help me better appreciate the unique value propositions of each project.