Okay. It doesn’t understand the information or concepts it is using.
That's just utter nonsense. ChatGPT by every definition of the word very much understands a lot of what it is talking about. People complaining about ChatGPT not "understanding" seems to have a hard time grasping how insanely difficult it is to produce natural language answers and how much you need to understand of the context to do so successfully.
It can’t reliably do basic maths
Neither can many humans, but my $5 calculator is great at it. There are without a doubt a lot of things that ChatGPT can't do, sometimes fundamentally so, like math. It can't do loops and it doesn't even get to see the digits of the numbers it should calculate on, so not a terribly big surprise that it can't do math very well. English language, and a whole bunch of other ones, on the other side, that it understands surprisingly well.
Basically, if you want to complain about ChatGPT, complain about things it actually gets wrong, saying "it doesn't understand" just makes you sound like a parrot and note even a clover one.