Fly.io
fortrabbit is a Fly alternative you may want to evaluate when looking for a modern PHP PaaS.
# About Fly.io
Jack of all trades. Fly distributes Firecracker microVM around the globe. While Docker and template deployment options are still available, registration and configuration are carried out through Fly's CLI tool called flyctl. The CLI app for deployment is comfortable and easy to use, but as complexity grows, console comfort may diminish.
Fly's king feature is its global distribution capabilities. If you don't require this functionality, it might be worth considering alternatives both above and below Fly.
# Why fortrabbit
Like Fly, fortrabbit is a PaaS-like service. fortrabbit on the other side has a higher grade of abstraction. It's more zoomed in to the specific requirements of PHP hosting. It encourages the use of modern paradigms, yet it is backwards compatible.