Nice! One small thing I noticed: it looks like you don't have compression turned up all the way. You might be able to save a lot of bandwidth if you use the most aggressive brotli settings for everything that's sent over SMS
frogfind.com - default: 3 messages :: new: 3 messages
lite.cnn.com - default: 43 messages :: new: 44 messages
text.npr.org - default: 8 messages :: new: 8 messages
"NFL Suspends 5 Players for Gambling" article: default: 15 messages :: new: 15 messages
Seems like either I haven't properly implemented the dictionary, or the default compression level is already set to max.