The purpose of the Accordion UI pattern is to enable fast access to the content behind headlines while maintaining equally fast access to the other items in the list.
One of the best examples of the accordions with the variable content size I can remember is Google Inbox.
Actually, they implemented hierarchical accordions. In the given example I have opened the group of Finance tagged messages.
Let's check their solution against the first 7 Usability Heuristics.
Visibility of system status.
This one is done perfectly on a desktop. You clearly see where you are inside the app.
Match between system and the real world.
Material Design reflects qualities of the physical word to form a spatial model that is familiar to users and can be applied to convey elements/components hierarchy.
User control and freedom
Again, you can access all necessary actions, previous or next items and close the content easily. Due to the limited space it is a bit more complicated on mobile.
Consistency and standards
This point is probably is the most questionable in your case. How you are going to deal with similar cases in other part of the app or web site.
This one is more about how fast the user can close the content if it is not what is needed. In case of Inbox app you can click on any element outside of the expanded area.
Recognition rather than recall
The accordion pattern if it is consistently implemented is quite proliferated to be considered safe here.
Flexibility and efficiency of use
This is basically why this UI pattern was invented.
Usability wise it is good to use. One can think that the accordion plays better if you have many items and the content length of these items is quite small so the user can jump to the next item right after after reading the open one. I think if the overall navigation is done right the accordion is also good for much longer articles as showing next items after the open article removes additional friction of going to separate menu or page to consume more content.