They just didn't use the right SD card. You need a class 11 Super ULTRA Extreme SD card made by some specific brand.
All the way back in Slashdot Effect days I recall a couple of people getting clever with Referer (sic) headers to detect someone on a tech news site linking to your website. In those cases they would redirect to a public cache, like Google's, reducing origin server traffic to a few packets per request.
I always found that to be way more clever than people gave it credit for.
So what you need to do, if you are serious about this micro server business, is buy a 1.5TB optane 905p and slot it into a pcie x4 to m.2 adapter. From there you will need a M.2 nvme to usb converter(make sure you don't get a SATA-only one). I like to strip out the inside of a tuff nano, but any will do. Now that you have your drive basics setup, you will need a type c to type a usb cable so that you can plug this into a Pi4. You could use the usb c port on the Pi4, but then how will you power the pi4, dummie? From there you will have to write a small driver that translates sd protocol commands to usb mass storage commands. Now get some wires and solder the Pi4's GPIO pins (the ones you used as I/O for your driver) to the micro sd pins on the adapter. And that's it, now you have a real SD card that is actually fast enough to run your server from an SDIO adapter! Wasn't that easy? Plus this way you didn't have to give $am$ung or $andisk any of your money.