I don't think there's a reason to be sad about it. There are plenty of e.g. maintenance jobs in the industry, and people who are passionate about programming may not be the best fit for this niche - it's boring, and sometimes you feel the urge to re-invent a few wheels even in detriment to actual business needs. For not-so-passionate however it's a good place - minimize efforts while having good salary.
I wouldn't be surprised if people who just program for a paycheck are the majority of employees in many offices. I know they're a tiny minority in a lot of the places I've worked at. That's not a boast or a coincidence - humans cluster in tribes based on shared values. I don't consider myself part of the same community as people who show up to work to close jira tickets and collect a paycheck.
This is why I keep my mouth shut IRL about just wanting the paycheck. I'd imagine a lot more than a tiny minority of people are just there for the job where you've worked. We just keep our mouths shut because the passionate folks judge us paycheckers.
But while you are at your job anyway, might as well make it slightly less of a drudgery while you are at it.
(Eg I quite like functional programming. Both because I like the style of thinking, but also because I don't trust myself nor anyone else with code; and eg a heavy emphasis on immutability means that I'm less likely to get woken up in the middle of the night with some production problem.)
Taking a mercenary attitude towards work works just fine for me, and keeps me overall happier.
Per your example, I like FP and immutability for the same reasons (won't get paged as much), and I'm always reading to stay up on my game, but it's still just work. If you worked with me, you'd probably think I live and breath this stuff as a passion because I put so much time in to stay so much on top of the tools available. But I hate programming. Hell, you might even say my hate of it drives mastery in the same way your passion drives your mastery. To me, it's just a tool by which to automate things I do care about (and retire younger than I could in other roles).
About FP and immutability specifically:
You don't have to go full on and re-write everything in Haskell. Small scale decisions can already make your life easier without much disruption. Eg if you are using Python, by default stick your information in frozen dataclasses, and only deviate from that with good reason.
Another thing I have a minor passion for is to as much as possible handle corner cases in the main line of the code.
Eg instead of having a big 'if' at the start of your function to handle an empty list and return early, try to make sure that the main logic can deal with empty lists just fine.
After all, the simpler your control flow, the easier it is to get code coverage in tests and production.
(I mention `and production', because in practice, lots of code is battle-hardened instead of sufficiently tested.)
you were passionate, found a job that claimed to match your passion and later found out otherwise. rinse and repeat multiple times, and there you go.
soon you started to be paycheck only at your day job and passionate off hours in your free time.
Their real passion is a having a band, or hiking, traveling, etc. And programming is just a way to fund those activities.
Others feel that programming is something that unimportant people do because they feel entitled to become managers. But why would a person like to work for a person they can't learn anything from? a person that looks down on their job? Noone wants a manager like that.
Unfortunately the people that get excited building things is outnumbered by the people that is just in this for the money.