Just to clear a few things up, this is an albino corn snake- they are usually easily identifiable by the bright orange/red colour. A Burmese is usually seen as green/brown.
So it’s not idiotic for an inexperienced person to get albino versions confused.
Also, corn snakes are usually long and thin, this one is quite chubby which could be because it’s just eaten, pregnant or just fat.
Burmese are usually stockier.
All snakes can bite so it’s no use saying ‘corns snakes are harmless’. Corn snakes are usually a placid species and this one looks quite chilled. But an inexperienced person grabbing it by the head may well provoke it. A bite from a corn snake is pretty mild though and most of the time you don’t actually know it’s struck until you see pinpricks of blood.
Because it’s been pretty cold recently it’s probably not feeling very good which is why it’s not moved much.
If you do find a snake like this in your garden, you could put a bin or box down for it to crawl into, or over it to contain. Then call rspca or a local pet shop who may come and help.