There is no physical PSP release. In general very few minis have physical releases. The only US one is Puzzle Scape Mini (Which dropped the "Mini" from it's title for the physical.) and there's Multiple European ones. Super Fruit Fall has a UMD release in Europe, and then there's the Mega Minis Volume # Compilations (I believe there is 3) other than that, most minis were not released physically.
The reason so many Minis entries have boxarts on this site is because they are Fanmade Fakes, if you try and search these physical releases on sites like eBay they don't pop up. I don't remember exactly where they came from, but I asked Spike from CDRomance years ago and he said someone made them and the site scrapped them from somewhere (Sorry that's not the most reputable info, he deleted his Twitter) I bring this up because those fake boxarts have been getting used on a lot of ROM sites, and it's caused other sites to engage in accidentally historical revisionism by thinking they are real and reposting them. in addition to here, I've also been submitting the thumbs to GameFAQs where I was seeing that a lot. I've attached a picture of what the express raider page over there used to look like. The PSP boxart is fake, this is a digital only release on PSP.
This does not document European releases, only US ones, but here is the collector's Guide MarcZero made, hopefully that validates what I'm saying a bit more. This document and coresponding Excel sheet documents all 612 black-label games that were released on the PSP in the US.
https://www.dropbox.com/scl/fo/yphkxwm63pg2ghext27a9/AFSDqLfSi-7_wtQmk12_8eo?rlkey=x19vmbfc37m2vx773up1zl1ox&st=bxehn1ky&dl=0
Also sorry for taking so long to respond, all of the PlayStation Minis thumbnails I've submitted I've been recovering by hand, and I'm just now performing my cleanup sweep.