Assuming you have a Firefox derived browser installed, you could just add an EPUB extension to the browser.

I set up Mint on my parent’s PC a couple of years ago, and the amount of support I have had to provide has dropped to basically zero.

Mint is an Ubuntu derivative like Pop, so the package manager is apt. Synaptic is a gui for apt.

If you want to learn and use ansible, go for it, but it might be a bit more than you need. If you are just wanting to install the apps you want, you can just write a quick bash script that installs all the apps you want.

The file structure should be the same in Mint as Pop, so restoring your dot files should be straight forward.