I managed to quickly find another lot and bought it, now I own a 2018 MacBook Pro 15. It came without an operating system, which turned out to be quite a hassle. The Internet restore feature only downloads the factory operating system, which is High Sierra. However, I encountered an error when trying to install it.
I researched the issue online and discovered that you need to fix the date via terminal to proceed with the installation. “Nice” and “friendly” work, Apple.
Anyway my goal was to install macOS Sonoma on the MacBook. Unfortunately, you can't create an installer officially on an older MacBook. To do this, I would need the macOS Sonoma app file, which can be converted into a bootable USB flash drive using terminal commands. However, I couldn't find the macOS Sonoma app file anywhere on the Internet—only in pkg format. My MacBook, being unsupported, wouldn’t allow me to unpack Sonoma pkg 🥴
To work around this, I created a Monterey installer since that's the latest operating system I can install on my 2015 MacBook. Now, I'm going to use this installer to set up the operating system on the 2018 MacBook.