tl;dr Your right thumb controls 3 actions and instead each finger should control 1 action. This remaps all movement controls to the shoulder buttons/triggers, keeping all the movement actions in one place. Link to the control scheme and directions at bottom.

Firstly, the addition of the "easy" control scheme was a wonderful idea and I commend the devs for including this. It's great for people struggling with the mere concept, but having moving separate from choosing your direction is vastly superior for fine movement. I'd prefer for this to be a checkable box as opposed to a whole control scheme, but that's a small point.

That said, let's take a look at the controls and your fingers. Right index finger controls forward movement. Left index finger controls grip. Left thumb controls direction. Right thumb controls looking upward for climbing, having the bird grab your tail, AND camera controls.This means your movement controls are literally strewn across all sections of the controller.

For me, I often struggled to remember which finger controlled what button, often holding down forward movement while trying to remember what to release in what order to perform the desired action.

To remedy the issue of having all of the movement controls across all of the controller, with three actions all dependant on your thumb, I recommend shifting the movement controls to the shoulder buttons and triggers. Right Trigger remains move forward and Left Trigger remains as grip. Right Bumper changes to look upward and Left Bumper calls the bird to lift your tail. Inexplicably, the stick buttons are not used as camera controls for this game despite being perfect for it. Right Stick Click becomes zoom in/out and Left Stick Click becomes reset camera. This allows you to dedicate one finger to one action each. Middle finger on the triggers, index finger on the bumpers, thumb on the sticks. You'll never have to move your fingers off the buttons, unless you want to pause or want to change your facial expression.

For the sake of being thorough, I'm going to list out what each button should be:
Actual Button = Button Mapping
Left Trigger = Left Trigger
Right Trigger = Right Trigger
Left Bumper = Y | Triangle
Right Bumper = A | Cross
Left Stick Click = Left Bumper
Right Stick Click = Right Bumper
The sticks still control movement and camera respectively, the d-pad still controls facial expressions, and the face buttons (A B X Y/Triangle, Circle, Cross, Square) remain the same in case you want to use them in a moment of panic and they're familiar.

URL for control scheme: steam://controllerconfig/544330/1164283647 (only way I know how to use it is to send it in a chat in Steam and then click on it)
(Note: it was created using a PS4 controller, however should function perfectly for an Xbox controller. It should also work for a Steam controller, however the grip buttons may provide you with an even more natural experience than this.)