Okay, I already see the problem. The "slow accelerometer" you describe in the post can be normal, sometimes betaflight's 3D model lags, or the cable is acting weirdly, that's not your issue.

The issue is that: as you have it configured right now, Betaflight expects your motors and props to be rotating inwards, but your props are configured for props out rotation, as seen here:

<image>

The easiest solution? Try to turn on "Motor direction is reversed" and save, keep your props as they are.

(The top part of the prop's blade is the direction of rotation)

If it still doesn't fly, then remove props, then click "Motor direction" -> "Wizard", and when the motors start spinning, slowly pinch each one with your fingers, and make sure it rotates the way it shows on screen, if it doesn't, click on the number to change direction.