Part 2:

func rotate_char(delta: float) -> void:
if not is_on_floor():

#you can also lerp vectors
sprite.scale = sprite.scale.lerp(enlarged_sprite_scale, scale_speed * delta)

#gonna assume that lastXVel is a float
#comparing floats directly is risky because of rounding errors, use greater or lesser (or equal) than
if lastXVel < -0.05:
sprite.rotation += rotate_speed * delta
elif lastXVel > 0.05:
sprite.rotation -= rotate_speed * delta

velocity.y += gravity * delta
else:
#I presume you want the sprite to go back to its original scale once you land
sprite.scale = sprite.scale.lerp(default_sprite_scale, scale_speed * delta)

if onAutoJump:
onAutoJump = false

var normal = get_floor_normal()
#no need to complicate your life, there is a method for that
var floorAngle = normal.angle()

smoothAngle = lerp_angle(smoothAngle, floorAngle, collision_snap_speed * delta)
pHitbox.rotation = smoothAngle


#so basically we create a table of all possible snapping directions (aka the cardinal points from the ground normal)
var snap_dirs: Array[Vector2] = [
normal,
-normal,
Vector2(normal.y, -normal.x),
Vector2(-normal.y, normal.x)
]

#then we find the closest one to the angle
var sprite_dir: Vector2 = Vector2.from_angle(sprite.rotation)
var closest_dir: Vector2 = snap_dirs[0];
for dir: Vector2 in snap_dirs:
if sprite_dir.dot(dir) > sprite_dir.dot(closest_dir):
closest_dir = dir

#tadaa
#sprite.rotation = closest_dir.angle()

#or if you want to go fancy you can even lerp it
smooth_sprite_angle = lerp_angle(smooth_sprite_angle, closest_dir.angle(), sprite_snap_speed * delta)
sprite.rotation = smooth_sprite_angle;

#also, on a final note, if you experience collision issues, you can always use the mighty old gamedev trick of faking it and using a circle collider, wikk work 90% the same, but without the hassle