@brooke Yeah, I found that RTL8156BG-based USB 2.5gbps adapters Just Work, and get full speed. I've got the USB-A version of the UGREEN adapter on Amazon, but they have a USB-C one too.
(Accidentally found it, even. I bought it a few years ago because it was cheap gigabit and used it in my router, only to find it was actually 2.5gbps when I got a 2.5gbps switch a few weeks ago.)