For having experience at a nuts and bolts protocol level, you seem to misstate or misunderstand some basic things.
The Lightning network is not a side chain. Maybe you’re confusing it with Liquid? It doesn’t have its own blocks. It’s a permissionless routing network built on top of the existing bitcoin blockchain. Two users can open a channel between each other, that is broadcast to the main chain, then it remains open processing unlimited transactions until the channel is closed. Then that is broadcast to the blockchain.
Since it is a permissionless network, any company can build on it or access it. The level of trust you give up is up to you. There are non custodial wallets, meaning you can have total control of you coins at all times.
Here’s some links
https://messari.io/resource/lightning-network
For users, a few manageable trade-offs exist which allow Lightning payments to be instant and extremely low-cost. Namely, Lightning users need a server with high uptime, a secure hot wallet, and must continuously backup their Lightning data. With these precautions, Lightning shares the trustless security and monetary scarcity properties of the core Bitcoin protocol.
https://apps.apple.com/us/app/muun-wallet/id1482037683