iphone 11 pro max keeps freezing due to lack of memory

my iphone 11 pro max keeps freezing - it only allows me (after hard reset) to enter password and look at one thing and then freezes. I'm wondering if it is due to lack of space - but because it will not allow me to open and look at this, I'm not sure (I do have set for auto back up to icloud). I tried connecting it to my Mac - but it only freezes and never shows up on the computer.