I agree its difficult to isolate exactly why a graft succeeded or failed, there are many variables involved. The whole up and down temperature for about two weeks after is a factor. My feeling is any abnormally-hot or abnormally-cold can be bad in that period, especially for the hard things like peaches, apricots, and persimmons.
Technique is also a factor. @Antmary, I am wondering if your wrappings are not helping warm things up - they are creating literal "greenhouses" in how the light enters the clear material but will not come back out. So this will improve your cool-temps odds. I use Doc Farwells on most of my grafts, it does not do that so is probably better for weather on the warm side.
I have had peaches start and then stall and die. My memory of these cases is there was a temperature shift of some sort, but a few times it was something else, e.g. the wrapping got exposed and it dried out, the graft got hit, etc.
Last night I was out in the orchard and found a 1' apricot graft had broken off. Fortunately it was hanging on by a bark thread and not dead yet so I put a splint on. It should be fine by the end of the season.