Optaplanner to solve waste collection problem

Any of those help The same way as you solve it if you want to store a many2many relationship in a relational database: create an extra Class.
For example: In cloud balancing, create a class Assignment that has a many2one relationship to Process and a many2one relationship to Computer. In curriculum course scheduling, this is already the case: there is a many2many relationship between Course and Period/Room, which is implemented by the class Lecture.

To fix the issue you can do The KIE Server API has changed in 7 series and wrapper is no longer required in the submit solution payload.
You need to send a POST to http://${kie-server}/services/rest/server/containers/${container_id}/solvers/${solver_id}/state/solving where the payload is just a planning problem (solution) object: ....

should help you out TL;DR but FWIW:
To scale above 1k locations you need to use NearBy selection. To scale above 10k locations, add Partitioned Search too.

hop of those help? A short answer to your question is No: PBS has no way to reclaim unused resources allocated to a job.
Since your computation is essentially a bunch of independent tasks, what you could and probably should do is try to split your job into 56 independent jobs each running an individual combination of model parameters and when all the jobs are finished you could run an additional job to collect and summarize the results. This is a well supported way of doing things. PBS provides has some useful features for this type of jobs such as array jobs and job dependencies.