Hi Sasha, I’m really sorry you’re going through this losing years worth of Hotmail messages especially when they’re needed for legal proof is incredibly stressful and disheartening.
Search all folders on Outlook.com set to All folders and“All time turn off any risky Rules/Sweep and remove strange forwarding try restoring from Deleted Items then Recoverable Items confirm no POP device is deleting mail from the server and check PCs for local PST/Archive files and if the emails were purged long ago be aware Outlook.com can’t restore beyond its retention window.
On which device and email app did you primarily access Hotmail between 2019 to 2023 and was any account set up as POP with delete from server after X days enabled?
Best regards
Lucky Charm