Solana is incredibly centralized compared to BTC. The higher the TPS on your base layer the harder it is to meet the hardware requirements to run a full node. Scaling in layers is the solution.
Eth's L2s are a confusing mess. They offer a variety of degrees of security and decentralization, some of them, like Polygon, are a network run with only 15 validators, yikes! And many of them are secured by a single bridge. There have been plenty of notable bridge hacks, it is not fun when your currency gets depegged.