In trying to troubleshoot, I wanted to ask: are other people experiencing issues with Gmail? I'm getting this error using the web client: "We’re sorry, but your account is temporarily unavailable. We apologize for the inconvenience and suggest trying again in a few minutes. You can view the Google Workspace Status Dashboard for the current status of the service. If the issue persists, please visit the Help Center." Google Workspace Status Dashboard doesn't seem to list any errors, so that's a clue it might just be me. I've tried logging in and out. iOS client works fine. I can access other sites like calendar and drive.
If others are having this issue, I deleted all forms of local storage (cookies, IndexDB, etc.) for the mail.google.com site, and that seems to have fixed the issue. It might be relevant that this happened after I upgraded Firefox.