The S series phones are the top of the range. So there are no budget ones. That said, there's no need to buy the latest if your budget doesn't stretch that far. Last years Series devices you can pick up much cheaper for instance
In addition to the excellent advice from @Glenntech , also consider a quality refurbished device.
Giffgaff for example have the S23 Ultra for about £500 and you don't have to sign up to them (buy a one money Goodybag then cancel but never use it, use your own sim).
How many more updates will the Galaxy S22 get? In case you need a reminder, your Galaxy S22, Galaxy S22+, or Galaxy S22 Ultra is eligible for Samsung's four-year Android upgrade policy and will receive four major OS upgrades