I'd love to give some advice here, how smart are we going? Pick all that apply to your dreams:
Keyless front door locks?
Smart light bulbs?
Smart speakers/question answerers (in every room?)? And how important is sound quality i.e. should they be super great speakers for music or are they only answering questions?
Smart Blinds and Curtains?
Smart bidet toilets?
Further to SW18_Dad's answer I've got a house full of LIFX bulbs who despite being first to market with smart bulbs have largely been overtaken by Philips Hue. The company was having issues but very luckily has just been bought by a big light supplier who will keep all their products working indefinitely.
I love my keyless lock, but it might not be for everyone - that's a Yale Keyless (not Keyfree, but depends on if you have a multipoint door or not)
I've got Alexa's everywhere, and a big screen Echo show in the Kitchen for timers
I don't have smart blinds and curtains, I want them, but don't have any plugs/sources of electricity so getting an electrician to do all that work and the subsequent presumed redecorating is limited
I love my Toto bidet toilet - I'm convinced they're the future
I use Arlo for home security cameras on doors/points of entry mainly because they had a totally wireless model (battery powered) - the downside is I have to charge these every 3-6 months
Speakers are largely Sonos Moves so that I only have to have a couple and can carry them between rooms or out to gardens. There's also a Sonos Beam TV sound bar that Alexa integrates with nicely.
I control a lot of this via a Home Assistant system that's very much only good if you're a technologist. Otherwise I'd look for things that integrate with Apple Homekit or Alexa for control. Aside from music I mostly just say "turn on the lights" / "turn off the lights" or run macros for certain combinations of lights like 'Alexa, evening' to enable a smart plug for fairy lights and turn on certain lights set to a certain evening-appropriate level of brightness.
One feature I really enjoy on the lights front is 'Alexa turn off *all* the lights' which will turn off lights house-wide which means you don't have to worry too much about turning off all the lights at night before going to bed because you can issue that command when you go to sleep