I would like to learn about the ethereum Blockchain

I would like to apply for a job in this domain a friend who already works there recommended me to learn about consensys products .

I would like to learn about Infiura,Arbitrum,codefi,conext and polygon. Where should I start ? I already know how Blockchain works but I'm more familiar with the smart chain rather than the ethereum Blockchain, and I would like to learn as much as I can about the ethereum ecosystem.