While there are voluntary shit-ass PMs, you can only afford to be not a shit-ass PM because the org isn’t squeezing you for all it can. Once it does, you’d have to make similar decisions. If you quit because you don’t agree with the way things are going, a compliant shit-ass PM will take your place, or no PM, and the people would end up in the place the parent described.
Leadership definitely drives a lot, but even with bad leadership a PM can and should do a lot to help here. I spent 5 of my years of PMing with an operations org that drove every big decision and I still did everything I could to protect my devs. I ended up in major burn out from it multiple times, but I don’t regret it.
Alerts that are waking devs up in the middle of the night have a user impact too, and a PM can and should communicate that impact and risk to the business side as part of why it needs to be prioritized. Alternatively, there might be a reason that the UI change is ultimately more valuable, and it’s the PM’s job to communicate why that is the priority to their devs. If developers with a Product team ever truly believe the reason they’re building something is just “because [insert team here] is excited about it,” then the PM failed at a critical responsibility.
