I don’t do cloud gaming so I know nothing about that but the overwhelming share of the size of the World updates is the Points of Interest and you can delete them seperately from the ‘3D cities’ which each World Update also contain.
Does cloud gaming give you your own storage space to put purchases in? Do you have ‘Content Manager’? It would be in ‘Content Manager’ where you would find a box at the top of the list which expands all entries into their sub-contents. The easiest way to find all the points of interest is probably to do a search for the word ‘interest’ and then uninstall those to clear up space.