Render a folder with rasters to an rgb image

qgisRasterToRenderedImage.py

from qgis.core import QgsRasterLayer
from PyQt5.QtCore import QFileInfo
import os

maindir = r'G:\kulturminner\New Folder (18)\501ad5c3\slope2'
files = [x for x in os.listdir(maindir) if x.endswith(".tif")]
outFolder = os.path.join(maindir, 'rendered')

def StringToRaster(file, filepath):
    # Check if string is provided

    fileInfo = QFileInfo(filepath)
    path = fileInfo.filePath()
    baseName = fileInfo.baseName()

    layer = QgsRasterLayer(path, baseName)
    QgsProject.instance().addMapLayer(layer)
    layer.loadNamedStyle(uri)
    pipe = QgsRasterPipe()
    renderer = layer.renderer()
    provider=layer.dataProvider()
    pipe.set(provider.clone())
    pipe.set(renderer.clone())
    
    extent = layer.extent()
    width, height = layer.width(), layer.height()
    crs = layer.crs().toWkt()
    
    file_writer = QgsRasterFileWriter(os.path.join(outFolder, file))

    file_writer.writeRaster(pipe,
                        width,
                        height,
                        extent,
                        layer.crs())

    if layer.isValid() is True:
        print ("Layer was loaded successfully!")

    else:
        print ("Unable to read basename and file path - Your string is probably invalid")
    QgsProject.instance().removeAllMapLayers() # Remove all layers

# Symbology
uri = r"C:\Users\OterLabb\symb_slope.qml"

if not os.path.exists(outFolder):
    os.makedirs(outFolder)

for file in files:
    filepath = os.path.join(maindir, file)
    print(filepath)
    StringToRaster(file, filepath)