Go into 'Apps' on your Android and in filter options turn on 'Show system apps', then look for 'Package installer/Application installer', the one that has a suspiciously large storage usage is the thing in which you have to go into, click 'Storage' and then 'Clear data'.
For some reason that thing fully duplicates the files you tried to install if the installation failed and it keeps duplicates of some data from things you installed over time. It's safe to clear it.
Also make sure you delete installation packages of games you installed already. Otherwise you have double the storage use.
And clearing cache of Chrome is advised if you're using it.