Independent contractors working for high value residential properties: what factors do you use to estimate labor costs? How does a property's architecture and topology influence hardware choices? How do I avoid getting ripped off?

I am building a custom property of larger size within the immediate future and I would like to know what buzzwords I should be looking for versus those that I should not when hiring someone to build a physical network infrastructure to last throughout my eventual retirement.

I am a DBA by trade, sysadmin (homelab-ish (Synology)) by hobby, and networking "connoisseur" through the basic fact that I know how to read Ubiquiti documentation. That said, I know a decent amount of IT.

However, when it comes to overall networking, I know little - especially at L1 and L2. Past those (and including L3) I still stumble through. My profession lives in a heavily virtual world where VLANs take precedence.

I have never had to consider how to run the fiber lines, or how to set up the physical firewall, or how to run the cable to the access points to the exterior gathering points. In my world, it's just there.

Now that I am building, I am at a loss for what I actually need to be looking for with my contactors.

How do I tell who is going to bullshit me with a cheap upfront cost that requires higher frequency of repair/upkeep versus those that are going to be upfront with the higher cost investment at the lower layers while also leaving the upper layers open for expansion?

I want to wisely spend upfront so that in my old age I can just "plug and play" as much as possible.

How can I determine the people and/or credentials that will offer this?