I recommend the MP02, with one caveat: don't buy it right now. Because there have historically been problems with Pigeon, you really ought to use Signal for Desktop at the same time as Pigeon, in case Pigeon starts having problems. But as of now you can't you can't connect the two (though Signal for Desktop keeps working fine if you already have them synced).
I've found the call quality and reliability on the MP02 to be great after a year of use.
[Edited to add: MP02 doesn't require a subscription.]
That's their MP02, different product line, which is pretty much just talk and text plus Signal ("Pigeon" on the MP02): https://www.punkt.ch/products/mp02-4g-minimalist-phone
I recommend the MP02, with one caveat: don't buy it right now. Because there have historically been problems with Pigeon, you really ought to use Signal for Desktop at the same time as Pigeon, in case Pigeon starts having problems. But as of now you can't you can't connect the two (though Signal for Desktop keeps working fine if you already have them synced).
I've found the call quality and reliability on the MP02 to be great after a year of use.
[Edited to add: MP02 doesn't require a subscription.]