It has been a year since the iPhone 13 showed that Apple was in a refinement path for the iPhone line with improved video across the board and the introduction of ProRes recording in 10 bits for some modes. The Slow motion capabilities had been capped at 1080p frame rates since the iPhones of old. The iPhone 14 has the same max 4k frame rate of 60p as the iPhone 13 but the sensor, image processor, and lenses have all been refined and improved.
Are high frame rates relegated to stay at 1080p forever on the Apple line? It has been 7 years of releases of capped 1080p at 120fps and 240fps with no other frame sizes getting a better spec. Most phones are also restricted but Sony, Huawei, and others have been delivering 120fps in 4k video modes for a couple of years now. The iPhone 14 seems to continue the trend of refinement without blowout frame rates at higher resolutions.