Cannot back up my ipad no matter what I try

Hello, I urgently need to back up my ipad and it won't work. Things that I have tried:

1) backing up using wifi and icloud. Non-starter, the progress bar stays at one percent and says 'calculating time remaining' until I get a message that says backup failed.

2)back up using pc and itunes. Won't work either. right when the back up is about to finish I get a pop up saying the ipad has disconnected(despite the connection being perfectly fine) no matter what cable I use(bought a new apple usb-c cable for this). For a local backup on my pc I lack storage space on the ssd it wants to back up to but I think it would just hit me with the same message.

3)backing up while connected to a mac. Same situation. says I have disconnected.

I have restarted the devices involved several times, bought a new cable and upgraded my icloud plan. No clue what to do from here to be honest. Any help is appreciated.