I can’t see a way that anyone would be able to give uncapped access to these models for a fixed price (unless you mean it’s scoped to your own use and not for company use? Even then, that’s still a risk to the provider.)
I use Msty a lot for personal use. I like its ability to fork conversations. Seems like a simple feature but even ChatGPT's UI, which everyone has tried to copy, is fairly limited by comparison.