Domain authority score is a made-up metric using a variety of criteria specified by each company. None of them are the same and they really don’t mean anything. The only numbers you need to concentrate on are traffic.
I wouldn’t pay too much attention to DA as a metric in all honesty.
If you really want to compare them, just use one platform to do it as it’s all relative. Like I say though, it doesn’t really do much justice to a sites performance and other metrics can tell you much more.
All of this metrics get all back links and show you average score OF ALL BACKLINKS. But if you look at GSC Links Google didn’t take a half of backlinks what ahrefs or semrush takes for scoring your website.