My free, open-source EC2 and RDS scheduler has supported multi-region, multi-account deployment since 2017. I've just updated github.com/sqlxpert/lights-off-aws to let Terraform users in big AWS organizations increase deployment concurrency instead of accepting conservative defaults. Advanced users can deploy to non-uniform region, organizational unit and AWS account combinations, rather than to the simple Cartesian product, regions × OUs. This feature request came all the way from a user in Finland, who was kind enough to write a basic PR. I re-checked AWS's official solution, Instance Scheduler. Despite Instance Scheduler's complexity, broad permissions, and external dependencies, AWS still wasn't providing immutable releases as of June, 2026. If you share my belief that simplicity is security, and if you care about independently-written alternatives to corporate software, please give Lights Off a try.