Hello,
Please try this and let me know if it help, feel free to reply this thread.
Be carefull while performing below steps, try this on one of test mailbox and then only apply to production use.
- Log in to the Exchange Admin Center (EAC) with your admin credentials.
- Navigate to "Recipients" > "Mailboxes".
- Select the user's mailbox that has the large Recoverable Items folder.
- Click on "Edit" (pencil icon).
- Scroll down to "Mailbox settings" and click on "More settings".
- Click on "Recoverable items" in the left menu.
- Select the items you want to delete (e.g., calendar items or all recoverable items).
- Click on "Delete" (trash can icon).
- Confirm the deletion by clicking "Yes" in the pop-up dialog.
Some helpfull article to refer- https://support.microsoft.com/en-us/windows/recover-lost-or-deleted-files-7bf065bf-f1ea-0a78-c1cf-7dcf51cc8bfc
https://video2.skills-academy.com/en-us/powershell/module/exchange/search-mailbox?view=exchange-ps
You can also try if you can get pwoershell script.
Please close this thread if issue resolved by accepting as answer.