Looking for recommendations of fully web based generation options

I have reached a point in my AI learning journey where the tools I'm using are proving inadequate, but I'm not yet ready to switch to a local hosted setup with something like ComfyUI. Even if I was willing to spend the money on a GPU upgrade, or cloud compute rental, I think I would still prefer a web based solution for now. Being able to dabble with a project on my mobile device when I have a few minutes of downtime is a real advantage. Here is what I am looking for: Fully browser or mobile app based. Built-in for advanced tools like control net and region prompts.