Seeking a Project Management Tool with Real-Time Capacity Updates Linked to Gantt Chart Adjustments

Hey everyone! We are exploring a new project management tool to get better visibility over our capacity across multiple retainer clients. Here is our setup: we have several retainer clients who have purchased anywhere from 20 to 80 hours a month with us. It’s typically up to us how we deploy those hours across a month. For each client, we scope out initiatives by breaking them into milestones and tasks with hour estimates. From there, it is up to us to define the order in which those initiatives get executed. The goal is to be able to move initiatives around and immediately see how that affects our weekly capacity, both for our team members and the retainer itself. For example, if we move an initiative for Client A, are we still within our hour allocation for them, or do we go over capacity? We have looked at several tools including ClickUp, Monday and Wrike. Most tools offer a Gantt view where you can move tasks and initiatives around and a workload viewer, but they are always decoupled. In practice, this means that when we move something in the Gantt chart, we have to manually cross-reference the workload view to understand the capacity impact — it does not update in real time. What we are really looking for is a tool where dragging a milestone on the Gantt chart immediately shows you how that change affects your weekly capacity per client. Has anyone solved this in an effective way? Whether it is a specific tool, a workaround, or a combination of tools, any tips would be welcome.