Do you sync your open tabs to your Microsoft account? (And were you syncing your open tabs to your Google account?)
Updates to browsers will sometimes wipe out open tabs, history, reading lists, etc. Unfortunately, this is unavoidable. But when you sync your browser, these items get repopulated in just a few seconds, because they are stored in your account
You don't have to sync your browser, whether Microsoft Edge or Chrome or Brave or Firefox, etc. But you miss out on the advantages of syncing when you don't sync.