Samsung phones have a low power mode on everything from s5 and up that disables every function of the phone (every sensor and radio) except texting and calling and 4 apps of your choice. It's much smarter to just disable your current phone than to completely replace it with something inferior and harder to use like an old flipphone. Samsung also makes modern flip phones running Android that have all the same simplicity of being able to be closed and of course not having apps installed if you so choose.
This is a really good solution for someone who wants to go nuclear on the smartphone, but isn't sure. You'll find out quick if your willpower is the main issue.
I've known for a long time that my willpower is the issue, because I've never been a fan of turning on notifications. I tend to keep it to only chat apps having notification rights, which would still translate to text notifications on a dumbphone. Pretty much any other time wasting I do on my phone is because I pull it out without prompting.
