Google moved up its estimated deadline for quantum preparedness in cryptography to 2029—only 33 months from now. That’s earlier than previous deadlines, and they proposed the new post-quantum migration deadline because of two new papers that comprise a big jump in the state of the technology. It’s ahead of schedule, but not altogether unexpected. Cryptographers and engineers have been working on this for years, and as the deadline gets closer, it’s not surprising to see more precise timeline estimates come up.
For what it’s worth, I tried as Portnoy suggested and searched for “quantum matrix and synapse”. I found this curious Cloudflare blog post about a serverless, post-quantum Matrix homeserver. I’m not too familiar with the Cloudflare offerings though.
https://blog.cloudflare.com/serverless-matrix-homeserver-workers/