PyQt QPainter Как применить сглаживание?

Есть нарисованный стрелочный индикатор. На красных секторах остаются глубокие неровности (заусенцы), хотя везде, где есть Painter, применил Antialiasing. Кроме того, по границе полукруга идут участки чёрного цвета. Как это убрать?

from PySide6.QtGui import QPainter, QColor, QPolygon, QPen, QPaintEvent, QConicalGradient, QGradient, QBrush, QRegion, QResizeEvent
from PySide6.QtCore import Signal, QSize, QRect, QPoint, Qt
from PySide6.QtWidgets import QWidget, QSizePolicy, QLabel
from typing import List, Tuple
import numpy


class ArrowPointerIndicator(QWidget):

    def __init__(self,
                 chunks: List[Tuple[float, QColor]],
                 lineWidth: int = 5,
                 parent: QWidget = None) ->None:
        super().__init__(parent)
        self.__arrowColor: QColor = QColor(255, 0, 0)
        self.__gradient: QGradient = None
        self.setChunks(chunks)
        self.__arrow = QPolygon([
            QPoint(-2, -80),
            QPoint(0, -100),
            QPoint(2, -80),
            QPoint(2, 10),
            QPoint(-2, 10),
            QPoint(-2, -80)
        ])
        self.__minimum = -10.0
        self.__maximum = 10.0
        self.__lineWidth = lineWidth
        self.__value: float = 0.0

    def arrowColor(self) ->QColor:
        return self.__arrowColor

    def setArrowColor(self, arrowColor: QColor) ->QColor:
        if self.__arrowColor == arrowColor:
            return
        self.__arrowColor = arrowColor
        self.update()

    def setChunks(self, chunks: List[Tuple[float, QColor]]) ->None:
        weightsSum: float = sum(item[0] for item in chunks)
        chunks = [(item[0] / weightsSum / 2, item[1]) for item in chunks]
        self.__gradient = QConicalGradient()
        passedWeight = 0.25
        for weight, color in chunks:
            self.__gradient.setColorAt(passedWeight, color)
            self.__gradient.setColorAt(passedWeight + weight - 0.0000000001, color)
            passedWeight += weight
        self.__gradient.setCenter(QPoint(0, 0))
        self.__gradient.setAngle(-90)
        self.update()

    def paintEvent(self, event: QPaintEvent) ->None:
        super().paintEvent(event)
        drawSize = min(self.width() / 2, self.height())
        painter = QPainter(self)
        painter.translate(self.width() / 2, self.height())
        painter.setRenderHint(QPainter.RenderHint.Antialiasing)
        self.__drawColorArc(drawSize, painter)
        self.__drawArrowPointer(drawSize, painter)

    def __drawColorArc(self, drawSize: int, painter: QPainter) ->None:
        drawingRect = QRect(-drawSize, -drawSize, 2 * drawSize, 2 * drawSize)
        excludeRect = QRect(-drawSize + self.__lineWidth, -drawSize + self.__lineWidth, 2 * (drawSize - self.__lineWidth), 2 * (drawSize - self.__lineWidth))
        painter.save()
        outerRegion = QRegion(drawingRect, QRegion.RegionType.Ellipse).subtracted(QRegion(excludeRect, QRegion.RegionType.Ellipse))
        painter.setClipRegion(outerRegion)
        painter.setBrush(QBrush(self.__gradient))
        painter.drawChord(drawingRect, 0, 180 * 16)
        painter.setRenderHint(QPainter.RenderHint.Antialiasing)
        painter.restore()

    def __drawArrowPointer(self, drawSize: int, painter: QPainter) ->None:
        painter.save()
        painter.setBrush(self.__arrowColor)
        painter.scale(drawSize / 100.0, drawSize / 100.0)
        painter.drawConvexPolygon(self.__arrow)
        painter.setRenderHint(QPainter.RenderHint.Antialiasing)
        painter.restore()


if __name__ == '__main__':
    from PySide6.QtWidgets import QApplication
    import sys
    app = QApplication(sys.argv)
    window = ArrowPointerIndicator(
            chunks=[
                (4, Qt.GlobalColor.white),
                (1, Qt.GlobalColor.red),
                (1, Qt.GlobalColor.white),
                (1, Qt.GlobalColor.red),
                (4, Qt.GlobalColor.white),
        ], lineWidth=1000000)
    window.show()
    sys.exit(app.exec())