We developed a SDK converter that takes the same JSON input as Direct Publisher and outputs the SDK for you to upload to Roku. The short story is we had a client with a bunch of channels that needed this work done, so in creating the process to seamlessly let them migrate, we sort of realized this would be a nice tool for anyone to have. Theres a free version and paid (non-recurring, one time) versions for monetization options, VAST Tag, etc.. We can also do the migration for you and build in any customization options you need.
Without further ado: https://sdkconverter.com/
Matt
https://sdkconverter.com/