i stacked using

from sklearn.ensemble import HistGradientBoostingRegressor, GradientBoostingRegressor, StackingRegressor

from sklearn.linear_model import RidgeCV

stack = StackingRegressor(
    estimators=[
        ('hgb', hgb),
        ('gbr', gbr)
    ],
    final_estimator=RidgeCV(),
    n_jobs=-1
)