Although the procedure is looking a bit of complex, it really isn’t if you follow the official steps provided by Microsoft BUT there is always a BUT.
First, I used this guide on migrating and I must warn you to be meticulous about it because you have to read and do the steps very carefully.
***The only thing that was missing was to allow less secure apps to get connected to GSuite and I got to that information via Google (not official documentation).***
Additional, the process of syncing could take even a few hours since the official Google bandwith limit for IMAP is 2500MB per day.
It is a cool feeling when you succeed in this kind of data migration!