does kantu support this at all? or it is purely local?
You can export Kantu macros in the well-known Selenium 2.9.1 HTML format and run them remotely. But the providers you mention support only the classic Selenium IDE commands that work in webdriver. Kantu has advanced features like data-driven testing, UI testing or real user simulation that are not supported by these platforms (yet?).
For now, the best solution is to create your own local or e. g. AWS or Azure based setup with Kantu. For this, Kantu has a command line API. Kantu works well with all CI/CD tools, for example Jenkins.