I'm not very good at explaining those "protocol layer" things, but for blockchain builders and bundles, retail investors only need to understand to a certain extent: when you place an order, it doesn't go directly into a block; often it's bundled together with others and inserted all at once. The advantage is it might be smoother, but the downside is sometimes you'll think, "Why did my trade execute here?" Basically, someone is acting as a transporter + queue manager between you and the chain.

My personal bottom line is three points: first, don't randomly click on unknown "faster and cheaper" channels; second, for large swaps, try to split them up or use more stable routing, don't crowd into the same pool with others; third, if you see inexplicable slippage or the route is overly long, suspect that you might have entered some private bundling or front-running environment. As for the deeper builder ecosystem and who collaborates with whom... it feels similar to recent modularization and the DeFi layer—developers are excited, but for ordinary users, just remember "who's helping you bundle, and why are you being front-run?" The rest, don’t let yourself get anxious about it.