In my experience: Fuck serverless.
If we're building anything bigger than a random script that does a small unit of work, never go for serverless. A company I recently worked for went with Serverless claiming that it would be less maintenance and overhead.
It absolutely was the worst thing I've ever seen at work. Our application state belonged at different places, we had to deal with many workarounds for simple things like error monitoring, logging, caching etc. Since there was no specific instance running our production code there was no visibility into our actual app configuration in production as well. Small and trivial things that you do in a minute in a platform like Ruby on Rails or Django would take hours if not days to achieve within this so-called blistering serverless setup.
On top of it, we had to go with DB providers like NeonDb and suffer from a massive latency. Add cold starts on top of this and the entire thing was a massive shitshow. Our idiot of a PM kept insisting that we keep serverless despite having all these problems. It was so painful and stupid overall.
Why was your PM making tech decisions?
Looks like you need the "quiet part" said out loud:
Chances are, the company was fishing for (or at least wouldn't mind) VC investment, which requires things being built a certain (complex and expensive) way like the top "startups" that recently got lots of VC funding.
Chances are, the company wanted an invite to a cloud provider's conference so they could brag about their (self-inflicted) problems and attract visibility (potentially translates to investment - see previous point).
Chances are, a lot of their engineering staff wanted certain resume points to potentially be able to work at such startups in the future.
Chances are, the company wanted some stories about how they're modern and "cloud-native" and how they're solving complex (self-inflicted) problems so they can post it on their engineering blog to attract talent (see previous point).
And so on.
Yes. Exactly. The company wanted to be "modern" in terms of tech stack and they kept getting buried in the thought that using serverless would keep them cool. The PM was also close friends with the CEO so everyone blindly nods to him.