Yeah... listen, I really don't think you have a choice. A RigidBody2D uses so much more CPU, and it's simply impossible to achieve what you want without bugs using it. It's simple to change, really. Here is a class I made, you can inherit from it. I made it so it's pretty simple to use.
extends KinematicBody2D
var outer_forces = Vector2(0, 0)
func move(_floor_normal = Vector2(0, 0), _slope_friction = 21, _max_bounces = 4, _floor_max_angle = 1.0472):
outer_forces = move_and_slide(outer_forces, _floor_normal, _slope_friction, _max_bounces, _floor_max_angle)
func apply_acceleration_x(_value):
outer_forces.x += _value
func apply_impulse_x(_value):
outer_forces.x = _value
func apply_force_x(_value):
outer_forces.x = lerp(outer_forces.x, _value, 0.5)
func apply_acceleration_y(_value):
outer_forces.y += _value
func apply_impulse_y(_value):
outer_forces.y = _value
func apply_force_y(_value):
outer_forces.y = lerp(outer_forces.y, _value, 0.5)
If you're going to switch, I'd recommend a gravity of 20. Just apply_acceleration_y(20)
every _physics_process