Depends entirely on what you prefer.
I have never owned a phone that I could see well in bright sunlight. Nor have I ever owned a phone that I'd want to chance knocking off the bars and it being run over by others. A common gps device, who cares if it gets run over, it's only got that days info on it anyhow. At least that's all mine has on it.
I'm assuming your list of numbered statements is why you might think a gps cyclometer is better than a phone. I won't disagree, but phones are getting better in weather resistance and ruggedness. Now if the phone makers would stop putting them in such fragile housings like glass or thin aluminum they'd be pretty rugged without a bulky outer box that has to be bought in addition to the phone. One of my older droid Maxx's had a kevlar body and it took drops and other hazards well without additional protection. But people didn't think that as stylish as the glass body of my moto x4 which had to be hidden in a outer box.... wow.. am I ranting? <grin>
But that sounds like I'm too pro phone use for cycling, and I personally am not. I keep my phone in my back jersey pocket where I feel it safe. I've had several bad crashes in the last five years and it survived there very well and in the one where I had a severe concussion it was easily found by the person that found me and they called my wife with it.
For a bike computer I want it on my bike stem or somewhere thereabouts or out front. I don't want it on my wrist because mostly I use if for gee-whiz info while riding such as to briefly glace at while going downhill. So I want both hands on the bars securely. Most of what I look at on a ride is just for gee-whiz purpose. I don't have a PM and I've learned to gauge perceived effort without having to know my HR or anything else. The device is mostly just to record data to look at after the ride. If it wasn't for the post ride review and analysis of my ride, I'd have no need for a cyclometer.
Which computer... I'm not a this brand is better than the other brand person. They all will work well for you if they have the features you want to use. Garmin, Wahoo and Lezyene have been good for a long time. Others are getting into the picture now too. I've been using Garmin handhelds for hiking and Garmin chart plotters for sailing since the mid 2000's. So circa 2010 it was natural to choose the Garmin Edge 500. I got a Edge 530 in 2020, but the 500 still works perfectly.