ECC UDIMM support on launch-day Threadripper 3000-series TRX40 motherboards from ASUS, ASRock, Gigabyte, MSI

TL;DR:
What are the launch-day TRX40 motherboards that have real-world support for ECC UDIMMs with single-bit error correction and two-bit error detection?

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Dear fellow rippers,

I'm planning on building a personal scientific computer based on a Threadripper 3000-series processor / TRX40 motherboard with ECC UDIMM RAM for tasks of Computational Fluid Dynamics (CFD).

I wonder what kind of experience early adopters are having with true ECC support on the various launch-day motherboards available. I would like to get real-world feedback on the true compatibility of ECC UDIMM modules on TRX40 motherboards.

I'm only interested in "true" ECC functionality here, which means correction of single-bit errors and identification of two-bit errors.
I want to have ECC UDIMMs on a TRX40 motherboard. Every word matters here: that is Error-Correction Code Unbuffered memory on a Threadripper 3000-Series motherboard.

Just to make it absolutely clear, I'm not interested in Threadripper TRX40 motherboards only seemingly booting just fine with ECC UDIMMs memory modules installed in DIMM slot but actually running as non-ECC memory. I don't want to have ECC UDIMMS installed on a TRX40 motherboard and finding out later on that only 8 of the 9 memory chips of ECC UDIMM modules are being used.
I'm also not interested in what the user manuals from manufacturers say, but really interested instead in real-world behavior.

This kind of topic would usually be covered on YouTube by people such as Wendell from Level1Techs (kudos to you, Wendell), but I can't seem to find relevant ressources online at the time of writing this request for information (admittedly early, only a week after the product launch of the Threadripper 3000-series).

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If you respond to this request to kindly share you personal experience, please mention:

• the make/name of your motherboard and
• the make/name/product identifier of your memory sticks.

Please also mention which method was used to asses the true support of ECC functionality (or lack thereof), be it with
"wmic MEMORYCHIP get DataWidth,TotalWidth" with TotalWidth 72 on Windows or better with
"wmic memphysical get memoryerrorcorrection" return code on Windows, be it with
"dmidecode --type memory " error correction type on Linux, be it with
memtest86+ or any other meaningful or accurate method.

I hope this post could end up serving as a first resource to people with a similar need.

Cheers!