Why lambda? Just run nodejs. The cloud has made otherwise smart people into unthinking drones. You don’t need any of the cloud stuff , except a Linux virtual machine. Stop drinking the cloud kool ade, it’s making things much more complex and expensive for questionable gain. Learn how to, you know, run software on a Linux computer.
I am pretty sure this is way more expansive to spend engineering time making it possible for server(s) to scale using kubernetes and stuff, than just using serverless.
And later with many users, we estimate what better be implemented manually to save money, because at this point it would actually save us money to employ a new engineer than continue paying serverless due to number of users.
Don't you think serverless makes sense?