I’m not sure it helps, because I don’t use chrome, but I had the same issue on firefox this morning, which was also conflated with a profile mess (maybe due to firefox recently switching to a separate profile per ff edition?). In any case, I ended up switching to a new profile, and my vault items are back, as well as in the extension. Maybe try to clear localstorage on top of cookies? I have no evidence it would help, it’s just a guess.
I am having this issue now only on Firefox. It might also be a Firefox profile issue, as it isn’t happening on Safari or the web vault. I’m going to try the suggestion of creating a new profile.
I have a similar case. My heart skipped a beat after logging into the Firefox (79.0 (64-bit)) plugin only to find it empty. After several rounds logging in/out with the same result, I checked this forum and found some reassurance all is not lost and after installing the desktop app. found my account is intact - phew!
Hope the FF plugin gets sorted soon as both are my primary tools.
Bitwarden is a great program I don’t hesitate to recommend.
You might want to invest some time into creating a backup. So even IF one day the vault is damaged/empty/whatever you still would have your data because of the last backup you created just days before doomsday.