It would seem that I'm on the ignore list so I'm not sure if I should even bother to offer advice to the OP, but just incase other people are reading this thread and wondering.
Llike my good friend Mr Rusty said - the question to ask yourself is why do you even need a smartphone, is there some specific function that a smartphone can give you that a dumbphone can't or is it just that other people are telling you that you need to have a modern smartphone. If you don't really need one and you just need a new phone then there are plenty of dumbphones out there that you can buy new, the Nokia 105 for example is well reviewed for what it is. Most of the basic phones that don't have smart capabilities seem to use 2G which is fine for just texting and calling but I don't know how that would effect coverage, can you still get 2G in an area where you would get 4/5G. Research is your friend and you will find reviews of most things on YouTube, if you start by searching for 'basic phones uk' in the search engine of your choice that will bring up specific models you can then look into in more depth.
As for whether you can use your phone while in foreign climes that will depend entirely on the phone company that you use and what you buy from them via your SIM card not the phone its self.
https://www.nokia.com/phones/en_gb/nokia-105
For the sake of disclosure I went straight from Blackberry to Apple and I've never used and android.