Are you talking about an exaggerated false grip like Al does for slow bar muscle ups? The bottom is actually the hardest part due to the strength and flexibility needed in the wrists.
I recommend trying a flex hang first. Do a regular flex hang with a normal overhand grip, then reorient your wrists one at a time while holding the top position. You can eventually do pull ups like this, but if you can’t come down to a full hang that’s fine go as low as you can while keeping the false grip. You will improve over time.
You can also do Australian pull ups with a false grip.