Hi @Russel1
There should be 2 flows, created and modified in one and deleted should be an other flow. There is a separate trigger called 'When a file is deleted'.

Once the file is deleted the above trigger is fired, try to use the action 'Get Files(properties only)' based on the filename from 'Folder A', once received the properties, use the 'File ID' to delete the same file in 'Folder B' by using the action 'Delete File' action.
Hope it helps, please like it or mark it as a solution if it resolves ur clarification or issue
-Sudharsan K...