It’s hard to know without more info, but just based on the pictures it looks like bed adhesion and possibly over/underheating the bed are both likely culprits. Have you ever printed anything as large as the x-shaped model in the pictures before? The single extruder that comes with the machine is notorious for having bed leveling problems.
It might be helpful if you post the bed leveling routine you use since that’ll be a good discussion starting point.
I’m having issues similar to this but I’m using the dual extruder which is supposed to have sensors to help with this problem. Might not be applicable but you’re free to following along here if it also helps.