Creating my first Smart Home

As the title implies, I'm creating my first Smart home!

I've come to the decision that it's between two ecosystems, Google (My ideal) and Amazon.

I own absolutely 0 of either, I was sold on google based on all the devices being under one brand (Doorbell, Thermostat, Outdoor Cameras and the design) but being on here i'm getting a bit put off.

I understand people don't enjoy the nest products not being great on the new assistant app, is that going to be an issue for me if everything is new aka not on nest?

Looking for honest thoughts, Cheers.