Hi @a_burggraafUPR9E. As far as I know, there is currently no standard method for suppressing or un-suppressing a 'collection' of component occurrences at one time. There are methods like that for 'features' (AssemblyComponentDefinition.SuppressFeatures & AssemblyComponentDefinition.UnsuppressFeatures), but not for component occurrences. Currently, I believe the best way to do something like that is by using the ModelStates (or LOD's in 2021 or older versions). One of the main things the ModelStates are responsible for is recording the suppression status of assembly components, features, and such (among many other uses).
If you often need to change suppression status of specific occurrences (or groups of occurrences), then create a custom ModelState for it, then select all the ones you want to set a certain way, then set them how you want them. That status change will then be recorded by the currently active ModelState. Now, whenever you want to suppress or un-suppress that group of occurrences, just activate that custom ModelState, or activate a different one. That change will usually happen much faster than when trying to make a change like that entirely by an iterating code based process.
However, if you need to control suppression status of occurrences in multiple levels of an assembly's structure, then that can get pretty complicated to manage by a single code based process started from the top level. This is because of what I mentioned above...each sub assembly has its own ModelStates, which record and control the suppression statuses of all the occurrences within that sub assembly. With that in mind, it is best to make sure that each sub assembly has its own custom ModelStates set-up in them, which can be used to control the suppression statuses of the occurrences within it. Then when you place an instance of that sub assembly within a higher level assembly, you can set the ModelState of that new occurrence (representing that sub assembly) to one of those custom ModelStates, to control that from a higher level, instead of trying to fully control every occurrence's status from the highest level.
Wesley Crihfield

(Not an Autodesk Employee)