On my April 2019 model (TB-x104F), there’s no screwed, metal ring. The battery is, instead lightly glued to the plastic base. There are 2 ‘ramps’ in the plastic on what would be the right side of your photo. I moved the unit to my outdoor barbeque in case mangling the lithium battery started a fire. I pushed my largest, flat blade screwdriver down each ramp, taking turns. Gradually I lifted the battery out. It looks curved and probably broken. I took the tablet inside and left the battery in the bbq.

The unit shown in this fixit session has a 26.6 wh battery while my April 2019 tablet claims only 18.7 wh. My unit’s battery is nearly square and is not held down by the screwed, metal ring shown in your photos.

The discussed cable doesn’t even exist on my April 2019 Lenovo. Good thing b/c a later comment indicated problems replacing the left side of that cable.

FWIW, my lenovo looks a bit different. I purchased it in the spring of 2019. The battery specs reveal differences too. No biggie…

Removing the cover was a struggle (for me, a newbie). Took 10 minutes+. I don’t have a plastic tool and the small screwdriver left marks. But a non-functioning tablet has zero value so …