Stream tends to lean more towards catchup rather than plan ahead!
In the TV guide new "shows" are generally prefixed with New: Unforgotten but some slip through the net.
There is on the home page a coming soon rail but that jumps about the menu and generally highlights Sky content. There is also Top 10 and the main rail captures anticipated or high profile content. But, you are right the more obscure shows or even new series tend to get lost unless they have viewer traction once aired and will pop up on the menu as described above.
Since having stream I've actually taken to reading the Radio Times once again and thankfully my local library publish an electronic version that is auto downloaded each week to my phone libby app for free.
As for the Playlist check under TV Shows and this will show any series added whether broadcast or not and then once broadcast or available check most recent that shows what is available with the newest published first on the row.
