This comes after a popular deals watcher Waio64 acquired an internal memo stating that digital games will only be available straight from PSN and that physical retailers would only be able to sell add-on content, virtual currency, and codes for the PlayStation Network service.
The Verge has confirmed this to be true as they have received the following statement from a Playstation spokesperson;
"We can confirm that as of April 1, 2019, Sony Interactive Entertainment will no longer offer full games through SIE’s Global Digital at Retail program. This decision was made in order to continue to align key businesses globally. To support full games and premium editions, SIE will introduce increased denominations at select retailers. DLC, add-ons, virtual currency, and season passes will still be available.”
In-short you can still buy games from retailers like gamestop, however you'll just need to buy codes for virtual currency and then spend them at Sony's online store.
Source: TheVerge