Deep breath, tamaris.
Tell us:
What you want to do with your phone - is the camera quality important; do you need lots of storage for apps, videos, music, books, files etc; do you play games; do you make video calls such as Zoom; do you use it to watch tv or stream video such as Netflix; do you want wireless charging; do you use it as a satnav?
How much do you want to spend on the phone? Android or Apple? Is the brand important?
What screen size do you want? Do you want a big screen which means a big phone or do you prefer something more compact?
Do you make lots of calls? Do you use a lot of 4G data (connect to the internet when you are away from home and not connected to a wifi hotspot)?
I've just found this which may be helpful
https://www.broadbandchoices.co.uk/guides/mobile/how-to-buy-the-best-mobile-phone