Depending on how much customization you have done, it might be easier and safer to just install the OS from scratch to the new disk. You'll also end up in a much more "clean" state afterwards.
- Your program settings, browser favorites, etc should all be stored in /home/
- Your system settings are generally stored in /etc
I would take a backup of the whole system (important!), then take a second copy of only these two folders (save all the permissions and ownership info, and also use sudo to access all the files in /etc !). After you have saved everything, wipe both disks, set them up like you want and reinstall all the software you need. Finally you can restore from these two folders.
You will not want to restore everything in /etc, just the files you have manually/indirectly edited, and also you will need to preserve the correct file permissions, so be careful on what you do there. Some files like /etc/fstab hold the information on how your disks are mounted, so you really don't want to restore those (same for /etc/passwd, systemd units, and many others). Basically restore selectively only what you need, or reconfigure the software again and just restore your /home
It shouldn't take as much time as it sounds, because most of the settings should be in your home folder, and you can reinstall all the software pretty quickly when you need them. You also won't have to fight all the problems if you end up with a weird/incomplete setup when moving the root.
There are some surviving national circuits like PagoBancomat (as the sibling comment from Scrollone) and Dankort (Denmark) and girocard (Germany). My personal impression is that they are slowly going out of fashion in favor of visa/mastercard only (probably because they can't offer better prices than them).
I don't see a solution to the duopoly, apart from lobbying politicians to support this national payment infrastructure. Especially in recent times I can also see how some governments might not want to rely entirely on two US companies for running their entire economy, so something might move on that side, so there's hope on that side.
The EU has already been moving on this front in the last years by forcing the banks to provide programming interfaces to initiate bank payments, and that's why you can now see more and more options to "pay by bank" online in EU. These online payments generally skip card circuits and run over normal SEPA bank transfers.
More info here on the last part: https://en.m.wikipedia.org/wiki/Payment_Services_Directive