If you're worried about traffic spikes, stick your site behind a caching proxy like Varnish or Cloudflare.

My main blog https://simonwillison.net/ runs as a Django+PostgreSQL app on Heroku behind Cloudflare, with a 15m cache TTL for every page.

This works perfectly. I survived a surprise Elon Musk tweet a few months ago which the server didn't even notice, because Cloudflare absorbed all the traffic: https://simonwillison.net/2023/Feb/17/analytics/