I'm frankly shocked this isn't available. There IS a Lock feature but it only locks to completion of the previous Module, not individual Lessons (which is ridiculous).
When you try to configure Lock, you get the option of choosing required lesson completion or required module completion, or both, but the dropdowns only give you the previous module, not the current one. This is a major flaw.
There are many use cases where you'd want to restrict lesson 2 until after lesson 1 is complete, restrict lesson 3 until lesson 2, etc.
We have sub-modules, which I thought might help, but they do not. I don't want to set up an automation for what should be a basic course progression feature. This also seems like a relatively easy fix.