Try jailbreaking to sideload apps first This looks useful: https://pangu8.com/jailbreak/ipod/
This looks like it’s specific for your version of iOS https://pangu8.com/ios-15-8-jailbreak/
Checkra1n even has Linux (and Mac) support https://checkra.in/
It hasn’t change since mid-2000s if you only talk about the installation process itself. Usually you would have at least some piece of hardware that wouldn’t work out of box and it used to be a lot of work until getting everything in place