please, could someone tell me if is there another parameter in the database configuration that could also improve the queries? Thanks a lot
Yes. There are lots of broker and client parameters that may affect performance. But there are no magic values that are appropriate for all situations. The proper configuration for you depends on your database, your system(s), your storage, and your application. We don't have details on any of those things so we can't suggest values for you.
What we do know is that you use the on-premise application of an application provider. Remember that is their responsibility to ensure that their application runs well in your environment. They own this problem until it is resolved to your satisfaction. You have done what they asked you to do: dump and load. (Did they provide you with guidance on doing that, or explain why they thought it would resolve your problem?) The ball is back in their court.
It doesn't help that they have you running a very old, and retired, version of OpenEdge. OE 11.3 was released 8 years ago and was retired 5 years ago. The current release is 12.4 and the current Long-Term Support (LTS) release is 12.2. You would have more performance-tuning options if you were using a newer release.
Tuning performance is a matter of starting with a reasonable configuration that takes advantage of available resources and then systematically identifying bottlenecks and eliminating them, finding the new bottlenecks, eliminating them, etc. In some cases, tuning is not enough. If your system just doesn't have enough resources or enough performance for your workload, database tuning alone will not raise performance to a level that satisfies users. Or if the application is badly written or designed, it may take changes to code, architecture, or schema to get the results you want.
Can you tell us more about the database? The size, the number of tables and indexes, the structure you used for your dump and load, the user count, the type of users and how they connect, the broker configuration; also the configuration of the OpenEdge clients.
For the database server: operating system type and version, CPUs, RAM, storage specifications.
For OpenEdge: the products you are using.
That would be a start.