Test automation is a fundamental part of Agile, but there are certain times where automation testing in agile is useless, like:
When there is an exhaustive level of documentation
When the requirements keep changing
One-time tasks and exploratory testing cases shouldn’t be automated
I recently came across a platform called QAppAssure which allows you to test on-cloud and on-field devices, across 100+ device, make and models, Integrate with Jira, CI/CD tools, and also use Appium, Calabash, Espresso, UI Automator, XCUITest. You can run unlimited parallel tests with the free trial pack.