I do own some, but they don't get used for much (browser-on-the-go, mostly).
Smartphones are definitely better all-rounders, but what I've come to adopt in recent years is a hobby of finding whatever tech/concept seems "best" to me (from any period in time) and then using that. Sometimes that means hardware from 1920, sometimes from today (e.g. I have a current-gen GPU to join the AI arms race). Sometimes that means a modern evolution of the concept without losing the spirit.
Easy examples:
* iPod -> Music player w/ FLAC + 1TB SD
* Gameboy -> Analogue Pocket (or sometimes original hardware)
* A modern standalone camera, etc.
It's sort of like living in the dream version of 2002 where tech stayed hopeful and fun (not sure if that's good or bad). Definitely brought me the most joy in tech I've had in years.
PDAs (and a _lot_ of tech from <2010) have the advantage of still being built entirely to serve the user. For my needs, I basically view it as day-planner or complement to a notepad and don't expect it to be a smartphone. My opinion is that these devices basically "solved" the digital calendar by ~1999 and that almost every calendar feature since (except maybe sharing) usually serves some other business need in addition to the user, or is just clunkier.
A PDA just wants to take good notes, manage the day's work, and be a simple extension of your mind. Most modern tasks (that don't require a network connection to be useful) have apps that still exist and don't spy on you: Food journals, encrypted notes, flashcards, project management, ebooks, cached news, Wordle, period trackers...
So, if your life today doesn't _depend_ on a specific vision of modernity, you don't miss out on much of it while benefiting from some forgotten UX benefits: Offline-first, great UI, week-long batteries (AAA if so inclined), Graffiti input, etc. :)