How to specify a local TTF file as a layout font in Plotly (Python) on PaaS?

I have a TrueType font file that I want to use as the layout font in a chart created with Plotly (Python). However, I can't set the font manually in the system because the chart is generated on PaaS.

I have tried using fig.update_layout(font_family=f"assets/{font_name}.ttf"), but it doesn't work and just changes the font to the standard one (Open Sans). I have also attempted to install the font using the link (like in this answer), but that doesn't work either.

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Here's a code snippet for reference:

import plotly.express as px

df = pd.DataFrame({"date": date, "data": data})

fig = px.area(df, x='date', y="data")
fig.update_layout(font_family=f"assets/{font_name}.ttf") # This line works incorrect

fig.write_image(f"images/{file_name}.png")

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How can I specify a local font file to use in my chart, or is there another way to set the font using code?

from How to specify a local TTF file as a layout font in Plotly (Python) on PaaS?