>> The redshift-distance relation holds for standard candles such as Cepheid variables and type-1a supernovae out to cosmological distances. That is some awfully strong evidence.
There is absolutely no proof. For example, is Andromeda (a nearby galaxy) moving away from our galaxy, or toward it? You have no clue.
>> Or you could skip that step, and go straight to solipsism.
Or, you could admit that astronomy has a history of spouting views that turned out to be science fiction.
It's moving towards us. The stellar spectra are, on average, slightly blueshifted. In order to say "you have no clue", you have to pretend the evidence doesn't exist.
[Note: I reject in advance any lawyering about it being blueshifted instead of redshifted, as if "proper motion" is beyond the ken of science. The blueshift of Andromeda no more disproves the redshift-distance relation than the motion of the moon around the Earth disproves the idea that the moon is attracted to the Earth.]
Or, you could admit that astronomy has a history of spouting views that turned out to be science fiction.
History counts for nothing. I judge the quality of the evidence. You ignore it.