> you will need to configure the bank to allow for direct transmission. This is a process that your bank will need to complete with you. How easy is this process? Are all banks required to provide such a service? How about countries outside the USA
This is frankly the actually difficult part of the process. ISO20022 is just a way to send messages, your actual commercial and settlement arrangements still need to be done. Banks are not required to provide such a service, you will specifically need an arrangement with a bank that offers that. Or more likely with an intermediary like Wise which will abstract the distractions like ISO20022 away from you.
[1] You can send prepared payment orders to Wise, but still need to log in and manually approve them.