First of all, answer with “no” to anything unplanned and unscheduled. Create a DMZ for the requests you welcomed and revisit them on each Monday. Prioritize whatever that comes from your users.

When enhancing system flexibility, aim for intentional simplicity—or as Einstein put it, "Keep it simple, but not simpler." Start with modularity with clear boundaries, ensuring components solve specific problems without overlapping or creating hidden dependencies. Apply progressive enhancement—focus on core functionality first and add features only when there's a validated need. A key but often overlooked practice is documenting trade-off decisions, ensuring future changes align with your original intent without introducing unnecessary complexity. Remember, true flexibility comes from systems that are adaptable yet minimal, not overloaded with features.

Reverse Engineer Features, Focus on Functions an data flows. Gather all required Top Level System features and structure them to similarities and identify necessary subfunctions. Delete redundancies and gather subfunctions to logical blocks. Assign all functions to closed subsystems and allocate necessary/ appropriate technology to realize these functions and assign responsibilities.(divide and conquer) In that way you reduce complexity and enable sustainability.

To avoid any complexity, first define a problem statement. Then try to de-clutter each twisted topic, then treat each topic with great care and see the dependencies, then give solution for all dependencies and individual items