A lot of what you're experiencing does not match any of the claims. And there's a bunch of claims you're making now that no one else did.
You realize there might be a usual problem going on, with "no-one's land". With enough small teams around, there's things where you just see things end to end that none who focus on their bits have. So what do you do?
I remember clearly a time, when I wrote clear and well-investigated bug reports about these, and then the ping-pong game starts. It often continues until there is either a developer with a system perspective or until I play personal relations on getting someone who wouldn't want to look at it to look at it to help pinpoint it further. I feel exhausted just thinking about this.
Today I run into something of this sort. And instead of writing a bug report, I made a list of reasonable expectations I was planning to talk about. Reasonable expectations are my claims on what I find would be reasonable to expect and I let the developers tell me I'm wrong - or find out that I'm right and then discuss the bugs I did not want to log against the end-user perspective claims that are not true after all, based on evidence. For now, until we've changed our software or our perceptions.
I realized this isn't something new for me. I've had great success with this before, with a difficult project manager of the past. The mechanism is just something I've never before labeled. I play a lot with the dynamics of communication while I deliver the messages as a tester. The dynamic of making me the one who is proven wrong on the reasonable claims turns around the feeling of how we'd talk about the exact same thing through a bug report.