To save on internet data, I tried to increase cache size as mentioned in https://docs.vrchat.com/docs/configuration-file. It is in the correct location, it is the correct format. It only has the "cache_size" specified, but my cache doesn't go over the default 20 GB. I have included my config.json file.
I also noticed that the text mentions the default is 20 GB, but the table claims the minimum is 30. Might be a documentation issue.
Edit: I deleted the config file, and my cache grew in size. The config file I thought was expanding my cache was actually limiting it.