Using Classic Outlook on Windows for personal email, calendar, and contact management
Within that link is offered the free OGCS (Outlook Google Calendar Sync), a GitHub solution developed since 2012: https://www.outlookgooglecalendarsync.com/ I have installed it and it is very satisfying.
Therefore, I recommend it as a totally working solution.
Cheers
Is this working effectively with M365 edition?
I gave it a try (M365) and it did not work just like that, meaning 'out of the box'. See my earlier post.
Maybe it works having with just 1 account, but I have Outlook with a few accounts linked (1 default, Outlook.com and some others). I don't know why it didn't and I confess: I haven't investigated any further.
I am using Outlook4Gmail for years now. It isn't free, but it is relatively user friendly. Maybe worth a try.