I'm surprised no one has had inspected a crash damaged 2021 spec Model 3 by now to see what's involved in this.
I've had a mobile ranger out twice in the last few months for minor rectification work, and both times he has sworn blind that an official retrofit is incoming, based solely on the number of enquiries his SC has been getting. He hasn't said he's had training on it yet, but he seemed to suggest discussions were further along than simple idle speculation.
I'd definitely go for an OEM retrofit if it became available, simply because of the "OEM warrantied" aspect of it, regardless of how much "better" Hansshow/TeslaOffer is.