It appears that the linked web page may also be running on a WiFi-enabled SD card and can't handle the load.
That'd be a nice project to work on.
Our goal was to build lowest possible energy consumption GPS tracker with "live" feedback, 2h delay was acceptable not ideal, 30min was just ideal. It was close to 30min on good weather.
I remember it used Ardunio Uno with xbee or zigbee with mesh module on radio, whichever had lower power consumption. GPS module was checking for fix every 30minutes, transmitting the location to master nodes which were sending it to our server.
Master nodes were located on hills without trees with solar-powerbanks, so even if there was no sun it would keep the nodes running for 2 months, GPS nodes were in areas without even GSM signal, and even on hills 3G was not guaranteed.
GPS nodes had replaceable rechargeable batteries, had to be changed every 3.5months. We didn't care about speed transmission.
We had budget of max. £15000 (including hardware, software and any legal fees and SIM card maintenance) for around 350 devices.
If you didn't want remote access you would not have to pay rx/tx costs.
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.