Thanks dongqtm.
Brave and Metamask were both up to date as far as I can tell. Version 1.61.109 Chromium: 120.0.6099.144 (Official Build) (arm64) and Version 11.7.2.
I’ve tried emptying the cache with a hard reload too, and restarting. Neither fixed the issue for me in a regular — not private — window, but opening Studio in a private window in Brave with Metamask has allowed me to connect to Sepolia. Thanks for the guidance.
I haven’t been able to mint an existing ERC-721 token to Sepolia, but that’s another issue.