@Rrez
There are a couple of ways that I can think of to do what you want.
When I switched to using badges with my statistics course, I had to rethink how I was using modules. I switched from the list of modules for the homepage to a content page for the homepage and that freed me up to use the module system for badges. That was good because my modules were getting really long and because we had multiple things going on at once, it was difficult to follow. I now have a content page for each week and rotate them.
The way that gives the most flexibility is to create a module for each badge and add the module requirements for that badge to that module.
This may mean adding requirements to multiple modules. Because the items are in different modules, I can have different requirements. For example, I give an "A" level badge for completion of all the assignments (score at least 1 point) and a "B" level badge for doing well (at least 75%) on the same assignments. For watching videos, students get the A level badge if they watch at least 50% of all the videos and a B level badge for watching at least 95% of all the videos. That means that someone who earns a B level automatically earns the A level as well.
If you have modules (badges) for chapters 1, 2, and 3, and then another for unit A, you would add the module items to unit A that were in chapter 1, chapter 2, and chapter 3. Then you would add things additional things to unit A such as the unit review and unit exam. The flexibility of this approach is that you don't have to include all of the items from chapters 1, 2, or 3 that you had around the first time. Let's say that each individual discussion had homework, a discussion, some quizzes, and a chapter exam. When it comes to the unit A badge, you don't care about the homework, discussions, or quizzes, you just want them to have scored 75% on the exams. When creating the unit A module, you would just add the requirements for the exams and leave off the other things.
This way has more module items within modules, but allows the student to clearly see what needs to be completed to get the badge by checking their progress on the modules page.
You can, as I did, end up with a lot of modules. I think I have around 65 in my class because that's how many badges students might earn.
A second way is to use module prerequisites.
If a student module complete chapters 1, 2, and 3 to earn the unit A badge, then you could have modules for chapter 1, chapter 2, chapter 3, and unit A. The unit A module would have a prerequisite of chapter 1, chapter 2, chapter 3, and then any other items that you needed the student to complete such as completing the review and exam for the unit.
The problem with using prerequisites is that a student is precluded from accessing the content in the module if they haven't met the prerequisites. If you set a requirement that a student had to complete the chapter 1 exam with 75% of better so they can earn the chapter 1 badge, then using prerequisite of chapter 1 to access the unit A module would keep that student from taking the unit A exam. That might be what you want if you are using mastery learning, but if you're using the badges to reward, rather than enforce, it probably isn't what you want.
If you are using mastery learning, then this approach would allow you to still use the modules page as your homepage as you're not taking over the module system just for badges.
Module prerequisites can only use modules that appear before it in the structure. In my other classes that use modules as the homepage, I like to rotate my modules to keep the current one at the top so students don't have to scroll through a lot to get to the current assignments. That would not be possible if I was using module prerequisites.