Use the GPT-4 Mobile model on the ChatGPT web interface. It also provides the ability to switch to other models for added flexibility. Generally, this script does not conflict with other popular ChatGPT scripts.
< Feedback op ChatGPT Model Switcher (Supports GPT-4 Mobile and All Available Models)
This Userscript doesn't work, it just shows ChatGPT 3.5 and Mobile options. It doesn't change it to ChatGPT4.