Database staging environment for non-IT personnel

Usually a decent environment would be made of at least DEV -> TEST -> PRE-PROD -> PROD. Development would normally have access to develop in DEV, acceptance testing in TEST and IT to release in PRE and PROD. If you use source control you will avoid problems around editing the same piece of code by different devs at the same time.

Technically you only need schema to be the same as in prod and not need production data below pre-prod but if you are ok with having prod data outside prod environment t you could have an automated restores into dev/test. I have done similar work with Visual Cron and it works wonders.

Likely in order to stay compliant IT personnel will have to release changes into pre and prod so to make this easier and more resilient you could go down the route of automated deployments.

Here is my experience:

Originally, we had a central development environment called simserver. Developers would test things simultaneously and it got messy.

Now, each developer has a local simserver that they deploy to for testing. Once they say it's ready, it gets pushed to the quality assurance (QA) environment. We have jira test cases for anything that needs to be checked, plus we test the new additions again (we have dedicated QA staff who don't do development; just QA).

Then it gets pushed live.

Making a local simserver is logical and easy. Once you get VM templates ready, the developers just deploy them on their personal computer (without access to the rest of the network -- just their local computer).

I agree with @Marcin Gminiski's answer that you ideally want to have an environment that mimics functionality available in your production environment. Although my 2 cents on the matter all come down to, "What can you afford?" Budget constraints are often the killer of good process, so really what you can afford will determine the complexity/elegance of your final solution.

Because you mention your IT department is lacking in time and staff to stage an environment for you, are you (or rather is your department/manager) able to bring any funding to the table? Procuring a small amount of annual funding would open up the possibility to look at the cloud. Cloud providers offer everything you need, and some solutions even include the appropriate licenses which is often your largest cost as it relates to Oracle. If you're not throwing sensitive data into this environment, the cloud becomes even more appealing.

There are all manner of cloud options available out there, but I'll point you toward Oracle RDS instances on AWS solely because they offer a License Included option, and you can turn it off when you're not using it to further minimize costs. An equivalent may exist on other cloud providers, but many cloud providers I'm familiar with require you Bring Your Own License (BYOL) for Oracle-based solutions instead of offering an inclusive license.

Final note here, an AWS RDS instance is ONLY the database, so any app-server infrastructure you also need would have to be be accounted for in addition. The cloud is a great option if you need a quick environment to test functionality out with, all while being a cost-effective approach; just make sure you keep on top of it and turn things off so you're not paying for idle servers.