My experience with Beanstalk was much the same had the feeling of a lot of hacky Ruby, Python scripts thrown together. Logs in random place, sometimes would get "stuck"
Current project uses GCP App Engine "Flexible" which is easier and seems to be built on better foundations than Beanstalk. Build a docker image and run. Although like you we could skip the docker shenanigans and just need a JRE to run our uber .jar (distroless https://github.com/GoogleContainerTools/distroless/tree/mast... makes a basic JVM docker container easy)
Current project uses GCP App Engine "Flexible" which is easier and seems to be built on better foundations than Beanstalk. Build a docker image and run. Although like you we could skip the docker shenanigans and just need a JRE to run our uber .jar (distroless https://github.com/GoogleContainerTools/distroless/tree/mast... makes a basic JVM docker container easy)