Are you exploring Layer 2 (L2) solutions?

Yes we are. We are live on Polygon since July'21.

What is the difference between ERC-721 and ERC-1155 tokens?

ERC721 tokens represent unique assets, where every token is attached to a different identifier— these tokens can never be duplicated, where no one token is equal. ERC1155 is a new token standard that brings in the idea of semi-fungibility and allows for the creation of multiple types of tokens in the same contract. This means that multiple copies of the same unique asset asset can be minted. See also:
Choosing an NFT Contract: Do you own Fungible Non-Fungibles?

What is the difference between Charged Particles NFTs (ERC-721) and ERC-998

Researched this initially, and didn’t go for it. Actually not that “composable” if tokens aren’t 998 in some structures. Also doesn't clearly support platform-based rewards such as $COMP. 721 is the standard for NFTs, so easy to trade on 3rd party marketplaces. With Charged Particles we can open support for additional types of Tokens (e.g. 1155, or 998).
- 998 is a token standard, can be built on top instead of ERC721.
- Showing that it’s possible, but you’d have to build the NFTs
- Composable only with other ERC-998 Tokens. Very limiting standard.
- Old standard, not updated for current DeFi
- Overly complex, what we’re doing is more efficient (cheaper gas) and easier. Supports much more token types - e.g LP Tokens, Other ERC-721, Other ERC-1155, Even ERC-998, etc.
If 998 Held cDAI, would have to build functionality to claim COMP & cDAI interest. Standard doesn’t allow for that flexibility. In short, they look similar, but ours is much more flexible

Where can I learn more about NFTs in general?

OpenSea’s “NFT Bible” is a fantastic resource to find out about NFTs.