Sony has done an interview with IGN, in which they state that Marvel’s Avengers and Borderlands 3 on PS Now are the PS4 versions.
Previously, we all thought that the current version would be available to PlayStation Now, but this is not the case. If you wish to have the latest versions, you would need to purchase them, as confirmed by both Square Enix and Push Square. One good thing is that the saved data from your PS4 is transferrable to the PlayStation 5.
You can play Marvel’s Avengers until July 5th, while Borderlands 3 will be playable on PS Now until September 29th.