Serverless took over that niche. First with AWS Lambda & Google Cloud functions and nowadays solutions, like Google Cloud Run, do the same thing as Dokku & co without having to care about the ops part. They still make sense for the ones who use cloud providers with less offerings like Digital Ocean and don't want to deal with Kubernetes
Ansible is good enough for me <a href="https://github.com/cupnoodle/rails-ansible" rel="nofollow">https://github.com/cupnoodle/rails-ansible</a>