I think getting a landline if you don't already have one would be very tricky, if not impossible, though, I don't know a lot about landlines. I've read some contradictory stuff on the internet, some say that they will be phased out soon. I think those in rural areas still can have it in the USA. I also seen some landline service offers without the need of wi-fi (since some say landlines will stay on but they will be used via internet?). I don't know much about landlines so sorry for rambling.
I'd say your next best option is a flip-phone or a phone with a keyboard on it. While many brands are unusable/you can't get service on them many still work in 2025! I recommend looking up what works in the USA (I don't recommend importing them from Japan or Korea because a lot of them only work in their specific country, plus it's more expensive even if a lot look very cool). These types of phones are called "dumbphones" and I recommend the dumbphone reddit where you can gather a lot of information, including what phones work in what country and what features do they have (with some you can only have the apps included on that phone, but with others you can download it from the phone's app store). I know that CAT phones or Kyocera phones work in the USA, but there are also other options.
I don't have a dumbphone myself, though I would like to. I can't exactly do that right now. But I'm bringing my phone around less.
Hope this helped a little.