Ask HN: I want a modern 2-way pager with clamshell keyboard. Does this exist?

I came up with some ideas to put together something resembling option 2. My main focus is not having the ability to accept a phone call or voicemail, or rich media; privacy is a plus, but to be honest that was not my motivation. The desire for modern customary encryption mentioned in the post above was because iirc the old pager networks were more easily snooped than modern SMS. As long as the experience is compatible with an on par with SMS, I'm happy.

If I had a magic wand: ideally, this would operate just like a dumb phone, but without the ability to make calls, take pictures, browse the net, anything of that sort. I just want to activate the display, see a list of SMS messages or contacts, and respond to them. Wifi interfaces and all that would diminish the experience for me.

I'm thinking if I wanted to put this together for fun, it'd be most likely to happen in a pocket size (hopefully without JNCO jeans) by using a small raspberry pi, small e-ink module, some type of mobile radio like an LTE shield w/ sim if that exists, and maybe for the first iteration a chopped up tiny keyboard. Slap it all together between a few layers of acrylic and it could work.

Alas, currently blocked and limited to pen and paper by the lack of raspberry pi stock available.

2-way pagers worked for SMS, that's essentially what I'm looking for, but on modern hardware, meaning I'd rather it be rechargeable through a port than have a AA battery slot, maybe a microsd slot for my contacts and messages.

The existing 2-way pagers work over conventional networks as well as radio networks that relay SMS and email through a gateway, which is why I specified that I was not concerned which method, I just prefer that it does SMS, perhaps natively.

The recipient, as with 2-ways, can use any method or hardware of SMS to send/reply.