VAV

Hello, I was stuck outside of the UK since June 2020 and could not come back until now May 2021. The car was left in a garage all this time and was not driven/started for months. I tried jump-starting it using a NOCO BOOST and using another car but nothing happens. There is not even a sound, the lights don't come on. Would anybody have any ideas? Is this most likely just a zeroed out battery? Or am I doing something wrong? I am using the big bolt pin on the chassis as the ground terminal. I am really surprised that nothing happens. I would expect at least the starter motor to turn. The car is automatic, so I can't even release the brakes without power. The garage is super tight (I can barely get in), so not sure how to tow it if it comes to that. Any similar experiences? Any insights greatly appreciated.