I can tell you that inside Apple, they have something called the standard question, and it goes something like this: “What are you really trying to do?”

If you haven’t personally filed a bug report at feedbackassistant.apple.com, I recommend that you do so. Title it something like “Poor text quality on LoDPI display”, file it in the Displays component, and in the description explain what you’re seeing. Here’s the critical part: you want to attach images showing what looks bad and what looks better, and why the current behavior is a regression and since when (earlier macOS versions for subpixel AA, earlier GPUs for 2x 1x mode). If possible, use the same display, but get an image of historical macOS when it had subpixel AA, macOS with this 2x 1x mode, Windows 11, and then current macOS at the standard 1x mode. I’m not sure screenshots will capture it, you’ll probably need to use a camera.

I know how they think at Apple. If you come at them with a bug written like OP’s blog, they are going to say it behaves as designed. To get them to fix something, you have to be descriptive about what the real problem actually is: the text rendering looks bad. Then you have to explain what used to work and what you’ve tried and bring receipts (the images). Don’t write a novel; write the shortest bug that fully describes the real problem, includes all of the relevant information including macOS versions, hardware info, and display model, and the evidence of the problem, but don’t include a bunch of emotional text or extraneous information (like SkyLight framework reverse engineering stuff).

Now you might say, “I’m not Apple’s free QA”, and you’ll be right. But, consider that you’re spending this time complaining about a problem online and you’ve spent good money on a display you’d like to use and it’s not working the way you want. Fair or not, you care about the outcome, and at this point you might as well take my advice and file a strong bug to make your case. Dupes help, OP should file one too, but be descriptive about the real problem, not proscriptive about bringing back the crazy workaround that they likely intentionally disabled because on the face of it, it makes no sense.

I do know that they read user bugs in the Displays component, because I have filed a few in there recently and they got fixed and they followed up with me about where they were fixed.