Office 365 Mailbox hold and admin recovering/searching for a user's deleted items

I am using an Office 365 Enterprise E3 subscription.

I have 2 simple, related questions:

How can I, as an administrator, ensure that emails deleted/soft-deleted/hard-deleted by a user can always remain recoverable, preferably by administrators only? The goal is for protecting emails against malicious deletions by users who wish to cover up their tracks.

Further to that question, how can I, as an administrator, search for and recover emails which were deleted by a specific user?

I found a lot of information on the above, but every time I try to do it in practice I get stuck. Litigation hold seems to be deprecated in favor of In-Place Hold, but on the other hand In-Place Hold is not straightforward to enable and manage. Also I cannot actually search for deleted and/or purged emails, there are several different KBs on the matter that either reference settings and buttons which are no longer in the O365 portal, or simply redirect me to Exchange on-prem articles...

The questions I stated above should be quite straightforward to understand, can someone guide me on what to do exactly to basically hold/protect mailboxes against email purges/hard-deleted, and how to actually search for and recover deleted items.