You're not losing access to digital games for the PSP just yet. When Sony reversed its decision to close the PS3 and the PS Vita storefronts back in April, it also said that the "PSP commerce functionality will retire on July 2nd, 2021 as planned." While that could be interpreted as Sony pulling the plug on all PSP downloads, new language that has popped up on both the US and the UK PlayStation websites (as spotted by Kotaku) shows that's not the case.
The PSP game store shut down way back in 2016, but you can still get games for the console through the PS3 and the PS Vita stores. Now that those storefronts aren't shutting down, you'll still be able to download PSP games through them, though there will be some limitations going forward. Starting on July 6th, you will no longer be able to search for games on the PSP itself or make any in-game purchases. Kotaku says the information first appeared on the UK website on June 28th, and it makes no mention of the previous July 2nd timeline.
When Sony backtracked on its plans to shutdown the PS3 and Vita stores, Sony Interactive Entertainment's CEO Jim Ryan said that it was clear the company "made the wrong decision." It's unclear if limiting PSP users' capability to search for titles or make in-game purchases is what Sony had in mind when it said that it will retire the console's "commerce functionality," or if it also changed its decision like it did with the PS3 and PS Vita stores' closure. Either way, what matters is that the PSP's digital library will continue being available for now.