How? The models aren't trained on compressed text tokens nor could they be if I understand it correctly. The models would have to uncompress before running the raw text through the model.
You can train your own with very very compressed, i mean you could even go down to each token=just 2 float numbers. It will train, but it will be terrible, because it can essentially only capture distance.
Prompting a good LLM to summarize the context is probably funnily enough the best way of actually "compressing" context