Logitech appear to have made the unifying receiver legacy tech now. Preferring their Bolt receiver going forward. This does have a USB-C receiver available but not supplied with their devices

https://www.amazon.com/dp/B0F9DWFSHP

Hmm... $30 and only being sold by third-party sellers there. That's not encouraging. Hope that's a temporary inventory shortage because of pent-up demand and not a sign that they barely intend to make any of these. Because I have a half drawer worth of various of the compact USB-A receivers and have literally never seen any USB-C equivalents in real life yet... It's time.