In my opinion, a lot of the complaints about attention are unfairly attributed to the device, when it's the rubbish installed on the device that causes these issues (social media, games, media streaming, news). This could also be extended to security and privacy.
As much as I'd love to go phoneless, I need it in case of emergencies (wife, kids, myself, a random stranger collapsing in the street). A dumbphone could provide that, but there's always going to be a bunch of one-off moments where some of the basic utilities of a smartphone are very useful.
I have a Pixel 5 (no third party apps, and small enough to slip into any pocket), with GPS turned off, battery saver on, very few apps installed (no games, streaming, social media, news), most of the default apps disabled, and notifications limited solely to calls and texts.
At home, the phone lives on its charging dock and acts as a home phone. When out and about, the phone sits in a pocket for 99% of the time I'm out. I only use utilities (like browser, maps) when it's necessary. I leave most thoughts until I get home, as anything important enough to want to check online is something that can wait a few minutes/hours.
According to the Google "Digital Wellbeing" app, which tracks phone/app usage, I spend less than 10 minutes each day on my phone, and unlock it 3/4 times each day (which is calls). I believe, due to my minimal use of the phone, Google collects very little of value about me. I just don't give it a chance to collect anything.
A lot of the alternatives to smartphones (eg. Lightphone, Librem 5, posted below) are very expensive ($300, $1300 respectively) and for that price, I feel you may as well buy a cheap smartphone and strip away all the excess or just buy a feature phone (Nokia 105 for $30). These companies are selling a lifestyle and talking piece.
You can buy a minimalistic phone like Lightphone, a feature phone, or some other workaround, but every now and then there'll be a situation where a quick check of Google Maps or some other mapping app would help. And that one check isn't going to tell Google all about your life. I'd rather have the utility there for those situations, than inconvenience a stranger in the street to use their phone.