Converted clips

Just curious but why when I import videos which have been taken with iphone shotcut wants to convert the clips on start up. Why would I use them when they are over twice the file size and always look dull compared to unconverted
xxx

Maybe your iPhone videos are shot in HDR (high dynamic range). Shotcut does not support HDR. Converting them converts to SDR (standard dynamic range).

No…am not using HDR on phone

I have not seen or experienced this more dull problem outside of HDR. You should share more details; the thumbnails you provided are not sufficient. We don’t know which conversion option you chose and whether whatever made those thumbnails are correct. Those thumbnails are not from an Apple app. You should show Shotcut’s Properties. You can open each in Shotcut use the video waveform scope to compare them graphically.
Also, you are not required to convert them. There is a Cancel button.