This is very common in almost all web companies since around 2015.

I've never seen a company with a simple infrastructure, no matter how simple their actual application actually is.

If you choose a slow dynamic language (Ruby/Python) your deployment has to be massively complicated; you have no choice about it.

For one simple reason: you will need a multitude of separate components to be made to work together.

You need many application instances because there's no way one machine can handle all your traffic: Ruby is just too slow.

A sharded database cluster as a source of truth:

You went through the effort of making several applications instances with a load balancer: you don't want a single database server to be a single point of failure.

A distributed redis/memcache index to accelerate queries and lower the pressure on the real database.

You might have several index-type engines for different types of quries. Most people use ElasticSearch in addition to Redis.

You need some system to manage all this complexity: monitor it, deploy new versions, rollback to a previous version, run migrations and monitor their state, etc etc.

This is the bare minimum. Most people have a setup that is way more complicated than this. I don't even know how they come up with these complexties, but they not only come up with frequently: they love it! To them it's a feature, not a bug.