The Vivo X500 Pro is another intriguing option. It has a smaller 6.36-inch AMOLED panel, but it is powered by the 2nm MediaTek Dimensity 9600 Pro, has terrific cameras with Zeiss tuning  and a decent-sized 5,300mAh battery. The difference between Oppo and Vivo's Pro models comes down to camera tuning — and having used both phones, I prefer what Vivo is doing. It is costlier at €1,399 ($1,566) for the 12GB/256GB version, but you're getting better cameras and faster hardware.

Vivo's Android 17-based OriginOS 7 has a modern interface with plenty of features, but like Oppo, there are Liquid Glass-esque design elements that may not be to everyone's liking. Other than that though, I didn't see any issues with the software or hardware, and Vivo's X500 Pro and the Find X10 are good choices if you're switching from OnePlus.

Another option is the Poco F9 Ultra. Although it doesn't have the latest hardware, it targets the value flagship niche, and it's down to £769 ($1,030) for the 16GB/512GB edition. POCO did a much better job with the cameras this generation, and I put it on par with the OnePlus 15. You also get a gargantuan 8,040mAh battery, fast charging and the cleanest onboard audio of any phone, with sound tuned by Bose.

Then there's the Redmagic 12 Pro. It has a distinct gaming-focused design, but if you want a phone with the best performance, the 12 Pro is hard to beat. You get Qualcomm's latest silicon, a huge 8,400mAh battery, 6.85-inch OLED panel with up to 185Hz refresh, and a front camera that's hidden underneath the panel, giving you an all-screen design. It runs Android 17 out of the box, and the best part is that it starts at $899 for the 12GB/256GB model. The cameras are strictly average, and the software is rather plain, but it's significantly cheaper than some of these other options. 

With OnePlus' exit, the list of flagship Android options has dwindled, but with the introduction of the Signature 27 and the Redmagic 12 Pro, there are decent choices available in the US. And if you're in Europe, the Find X10, Vivo X500, and POCO F9 Ultra offer a similar caliber of hardware and software feature-set, with better cameras.