Copy feature between layers with PyQGIS

So I think you need to drop the fields that you don't need from the new features you are creating in order for it to 'fit' into your simplified dataset. We can do this by finding the indexes of the fields that you would like to keep. As per this answer: https://gis.stackexchange.com/a/266431/91833:

field_ids = []
# Fieldnames to keep
fieldnames = set(['fid','nome','max_speed','codego_nacional','place','highway','super_sug_id','oneway','tool','admin_level'])
for field in layer.fields():
    if field.name() not in fieldnames:
      field_ids.append(layer.fields().indexFromName(field.name()))

And then creating a new vectorLayer in memory with:

L = QgsVectorLayer("Linestring?crs=EPSG:4326","foo","memory")

Append the original layers features to the new memory layer, and delete the attribues you don't want:

for feature in layer.getFeatures():
            features.append(feature)

L.startEditing()
L_data = L.dataProvider()
L_data.addFeatures(features)
L_data.deleteAttribues(field_ids)
L_data.updateFields()

simplified_features = [f for L.getFeatures()]

mapLayer.startEditing()
dataP = mapLayer.dataProvider()
dataP.addFeatures(simplified_features)
mapLayer.commitChanges()

I have not tested this but your code should look like this:

from qgis.core import *

mapLayer = QgsProject.instance().mapLayersByName("MySQL:forexeasy,host=localhost,port=3306 authcfg='z4s291g',tables=avenida_rua|layername=avenida_rua")[0]

# selecionar estrutura dos fields name
# criar um feature
# clonar os 
if (mapLayer.isValid()):
    layer = QgsVectorLayer("D:\\workstation\\qgis\\temp\\fid_62.shp", 'lay', 'ogr')

    if(layer.isValid()) :

        field_ids = []

        fieldnames = set(['fid','nome','max_speed','codego_nacional','place','highway','super_sug_id','oneway','tool','admin_level'])

        for field in layer.fields():
            if field.name() not in fieldnames:
                field_ids.append(layer.fieldNameIndex(field.name()))

        L = QgsVectorLayer("Linestring?crs=EPSG:4326","foo","memory")

        for feature in layer.getFeatures():
                    features.append(feature)

        L.startEditing()
        L_data = L.dataProvider()
        L_data.addFeatures(features)
        L_data.deleteAttribues(field_ids)
        L_data.updateFields()

        simplified_features = [f for f in L.getFeatures()]

        mapLayer.startEditing()
        dataP = mapLayer.dataProvider()
        dataP.addFeatures(simplified_features)
        mapLayer.commitChanges()