Your code sample is incomplete so it is impossible to reproduce.

Does it work if you simplify your plotting to this?

import matplotlib.pyplot as plt
import geopandas as gpd

df = gpd.read_file(r"C:\Users\bera\Desktop\gistest\world.geojson")
fig, axes = plt.subplots(nrows=3, ncols=1, figsize=(3, 6))

df.plot(ax=axes[0], color="red")
axes[0].set_title("Red")
df.plot(ax=axes[1], color="blue")
axes[1].set_title("Blue")
df.plot(ax=axes[2], color="green")
axes[2].set_title("Green")