In macOS Tahoe 26.0 and Orion 0.99.136-beta (WebKit 622.1.15.19.2), passwords are not filled form "3rd Party" (i.e. macOS passwords).
The iCloud extensions seems to be working fine.
Open the Passwords app and autofill, as it did in Sequoia.
Orion 0.99.136-beta (WebKit 622.1.15.19.2)
Tahoe (26)
