New to Patek

[train-time]

Greetings! Been a forum member for over 10 years but basically spent all my time in the Rolex section and owned Rolex and Tudor exclusively for the past several years. I'm considering going down the Patel "rabbit hole" for the first time. Don't know anything about the watches other that seeing them in an ADs case many years ago. We no longer have an AD in our state so it isn't easy to get the touch and feel of the various models.

I like the reference 5146 and am toying with buying one. I have seen used ones on some sites and also some new, but those would not be coming from an AD. I have many questions since I am not too familiar with the brand so here goes:

Should I only buy from an AD? Will there be warranty or service issues if I buy new from a TRF "trusted seller"? Will it hold it's value should I eventually decide that the "Journey" takes me in another direction? Is the reference 5146 an OK model to consider? I like it size and appearance.

I know that a Patek is a Patek and having seen them in a case many years ago know that they are one of the cherished brands and I would consider it to represent the end of my watch journey as I am getting up in age and about to retire. I would still have my Sub-Date as a daily wearer but think the Patek would be my ultimate piece to cherish as a grail for years to come.

Any thoughts from the experts would be greatly appreciated.

Thanks for any assistance.