Questions about Pure OS

Hello, I am trying to find more information about pure os.
What exactly is the difference between the operating system that runs on the phone verses the operating system that runs on a computer. It seems to me that the computer OS is just another Debian distribution. Is this the case with the OS on the phone as well? Can the phone run standard debian packages when standing alone or when connected to the external monitor? If so, does a standard debian package look normal running on the phone or is it similar to running a package in a libertine container on ubuntu touch?

Is there any way I can flash an android phone to with PURE OS to see if I like the mobile version of the operating system? I do not have the money to to buy a librem 5 phone if I am not 100% sure of how well it will run. I currently am using Ubuntu Touch on a Oneplus One, and it is unstable, with many features not working well. In your opinion, how stable is pure OS running on the phone, and how much more refined is it than Ubuntu Touch?

Thanks,
Ed

Hi Ed, my colleague Mladen replied to your question via email

Thank You.