Modern premium smartphones are bigger than 3 or 4 year old ones, and a lot more expensive.
If you're an Android fan, Samsung S series is hard to beat (ignoring cost), if you're an Apple user, iPhone 14 (go for Pro or Max versions if photos are important) is also an excellent phone.
Both these are huge steps up from things like S8/9 and iPhone 7/8/X in performance terms and photo capability. And both tend to get decent support from the manufacturer for a decent period of time, unlike many other brands of Android.
In the case of Android, I'd be more inclined to buy outright, and use a SIM only contract, as you get security and feature updates as soon as the handset manufacturer releases them, rather than waiting for your carrier to do so - and many don't bother, especially on less popular models. It usually works out cheaper anyway if you shop around for decent SIM only contracts.