You can ask Optimizely for an additional Development environment in DXP (ADE1) - Create a new Pipeline to deploy new project work to this environment and keep the other 3 environments for hotfixes
You could also utilise the Integration environment in the same manner and just have Prep and Prod for Hotfixes.
If you need the YML to build and deploy direct to prep and prod let me know
I use the Epinova extension for DevOps for deployment instead of promoting integration > preproduction > production in the paas portal.
It gives me all the flexibility I need.
We currently got standard Integration > Pre-Prod > Production deployment strategy for our DXP. But now we are working on one project that will be going to last a few months and we do need to showcase it to the stakeholders but no planning to push changes to the production (or even pre-prod) until the project is finished. How does everyone go around this challenge and keep pre-prod and production open for any new hotfix and release but keep working on a new feature that can't be pushed to live for the next few months?