On my tablet, I have my RSS reader which produces about 30 entries per day, of which I read 2 or 3 articles, and then I'm done for the day. If I put down the tablet to do something else, I have zero experience of "FOMO" because blog articles are experienced at a glacial time scale.
But also on my work laptop, we have Slack and Email and such on my laptop (only, no hand-held devices), and none of them have notifications enabled. Also, once I've read my mail to inbox zero, I close that tab. Then I'll open Slack (not both at once), and once I've caught up I close it. Then I do some productive work. I'll open them later when it's convenient for me.
I think that's an attitude I developed at some point in the past few years. All modern Internet-based tech wants your engagement, full of dark patterns (like making things disappear if you see it once or lift your finger), and you have to protect yourself from that. Choose devices, apps, services that keep you in control. Discard the ones that don't.