Your take on things, Reply, sounds about right to me. It also occurred to me that the OP might be subconsciously seeking the board’s “permission” to spend some money on a new unit. That would kind of explain his refusal to take action on any of the diagnostic steps and fixes he explicitly asked for.
Also, it seems the OP had similar concerns about the performance of his air conditioner a year ago, when many of the same issues came up:
https://boards.straightdope.com/sdmb/showthread.php?t=858115
From that thread:
The post above confused me a bit, because thus far the OP has insisted in this thread that the perceived drop in performance is recent:
He’s also repeatedly and emphatically rejected all suggestions that his AC unit is underpowered for the current conditions even though it was underpowered last year as well:

Joey said that he thinks the machine wasn’t up to it, and was not compromised. I disagree. […] I live here and I don’t think so.
It sounds to me like the unit has long been marginal on hotter days. It certainly was a year ago—and that was before he discovered his beloved over-the-door fans.
I’m a little surprised that the OP seems to have forgotten that his AC capacity was marginal last year, especially because it was marginal enough that he resolved to buy a new unit a year ago.
Incidentally, the OP struggled in last summer’s thread to get a handle on the concept of temperature deltas and how they might be measured, much as he has in this thread. To be frank, I suspected that the OP was, for some reason, being deliberately obtuse about the delta T concept—especially after being deliberately and passive-aggressively vague about exactly which air conditioner we’re discussing.
But reading through last year’s thread, I think Drad Dog’s confusion might be sincere. If it is, there’s obviously no shame in that.
———————————-
Drad Dog, this is one reason many of us have asked you to measure delta T: if you’d measured temperatures last year, you could have compared those numbers to this year’s to see if there had been an objective decrease in performance in the last 13 months. You’d also know how your original unit compares to the loaner they gave you. I’m not wagging my finger at you—I’m trying to explain why some of us are pushing for specifics. The tone of your responses makes me think you might not understand why we’re asking.
You’ve insisted on the primacy of your subjective impressions, saying things like “I know it’s not cooling like it used to. I’m here and you’re not, so you’ll just have to trust me.”
I’d gently suggest that perhaps you shouldn’t trust you. Richard Feynman famously said that “the first principle [of science] is that you must not fool yourself—and you are the easiest person to fool.”
People get habituated to things like temperature, humidity, scent and risk. Nearly everyone is much worse than they think at estimating things like that—myself included.
Many of us who have posted in this thread are problem solvers by nature and/or profession (as are the technicians who decided that your compressor works fine). We know from experience that we can’t help you in any substantial way without a few critical bits of information.
When you withhold such basic information as temperature deltas and even the make/model of the device in question, you make it really hard for us to engage the way you’ve asked us to.
Your OP asked, in part, how to respond to the warranty center’s assessment that your unit works fine. Well, the delta T measurement is critical to answering your question. That number would likely allow us to say either “the warranty people are full of it—push for a replacement” or “they’re right—your unit is operating within spec.”
You seem to expect an omelette while bristling at questions like “how many eggs are in the fridge?” and “what kind of cheese do you have?” IMHO, that’s odd and legitimately enervating. But my impressions aside, it’s also objectively unreasonable.