I hope they do release it. I was looking into getting the Legion Go back when it launched but all the reviews between it and the Ally made me realize how much I rely on SteamOS-specific features.
Is it possible you might be looking at this old support page from when MacOS first dropped support for 32 bit apps but Valve was still supporting the 32-bit client for older MacOS versions? The current page is this one. I doubt they'll be removing games from your libraries at any point, but the new article makes it clear that they aren't supporting the 32-bit Mojave Steam client or 32-bit games on Mac anymore and make no guarantees that they'll continue to work when the client stops getting updates.
After February 15th, 2024, we will no longer support macOS 10.14 or earlier and we are unable to guarantee continued functionality of 32-bit macOS games after that date.
What about it is misinformation? It's practically just Steam's own announcement worded differently. Everything in it is verifiable and supported by the Steam blog post.
The blog doesn't link to that support page because that support page isn't related to this. It's out of date and was written when MacOS originally dropped support for 32-bit apps starting with Catalina. Valve was letting people know that even though they wouldn't be able to play their 32-bit games if they update to Catalina, they would still be in their library and available to install on Mojave and earlier. Valve was still supporting the 32-bit Steam client back then.
That's an old support page from back when Apple originally dropped support for 32-bit apps, it wasn't written with the discontinuation of the 32-bit Mojave Steam Client in mind because at that point they were still supporting it. They won't be removing 32-bit games from your libraries, but the 32-bit Mojave Steam client will eventually stop working, and without any warning, when a future update inevitably breaks compatibility. They may still be in your library, but you wont have any way to install those 32-bit games anymore.
This article isn't stoking fear imo, it's very straightforward about what's happening here. At some indeterminate point in the future, there will be no more installing 32-bit MacOS games from Steam and anything you already have installed will presumably need to be run in offline mode because the client will stop working.
From what I can gather, it sounds like things will keep working until something changes on the back-end that leaves the old Steam client unable to connect anymore. I don't think they can't say when that will be exactly though because it depends on future updates.
The move means existing Steam Client installations on those operating systems will no longer receive updates of any kind, including security updates.
We expect the Steam client and games on these older operating systems to continue running for some time.
The company is encouraging all High Sierra and Mojave users to update "sooner rather than later" and noted that Apple ended security updates and technical support for both operating systems in December 2020 and October 2021, respectively.