Day 1 releases is one of the main draws of Game Pass. The Game Pass marketing site [1] has an entire section labeled "Play Day One" that says
"Be among the first to play the latest titles from Xbox Game Studios and ID@Xbox, available to Xbox Game Pass members the same day as their global release."
One down side my son discovered recently is when he went to play red dead redemption 2, which he only recently started, and it had been pulled. It was a little frustrating. Otherwise game pass has been a pretty good value.