If you're committed enough to ignoring the difference in the quantity of complaints that you'd need "evidence", I am pretty sure that we could present a signed listing of the complaints, notarized by God, and you still wouldn't believe it, so why should I bother?
I've been using it for a decade, and it's been quite good at predicting battery life under normal circumstances, and has worked as well as every other battery life estimate. Which is to say, it will obviously fail if you change workloads a lot, but that's fine. It still works.
But the key thing here is: "It wasn't before". So why didn't they take it out at any time during the previous decade? Why did that suddenly become a problem that required correction now, when it wasn't a problem at all in the past?
For years, Apple's fans (me among them) said "of course it's not perfect, it's an estimate, but if you know how estimates work, it's very useful". Now they take it out, and suddenly it was always awful and was never good, and they absolutely made things better by taking it out now. But they shouldn't have removed it ten years ago, or any time between then and now.
The fact that they removed it is irrelevant to what you perceive as "battery issues" because they feature is still there in activity monitor, and it doesn't change actual battery life so people who had problems before will still have problems now. Keep ignoring the logic though.
You can't make a claim on the quantity of complaints and say it's worse because you feel it's worse and have that be a fact. That's not how things work. Unless you can quantify it with actual numbers in some way it's not a fact, it's a feeling which is open to being called ******** if you can't provide actual numbers.