Budgets and Financials
In most organizations, budgets are an essential part of the business process. They deserve specialization to make them easier to understand. We can view budgets in two ways: as a constraint and as a resource.
Budget as a Resource
When we consider the budget as something we can spend, it clearly qualifies as a resource. This aligns with the Archimate definition: “Represents an asset owned or controlled by an individual or organization.” When modeled in this way, the concept of a budget, both in general and as a project budget, becomes clearer:

In the illustration, the resource is specialized to budget and further specialized to project budget. The latter specialization is necessary because the properties typically used in projects (which we will utilize in later annotations) differ from those of general (e.g., departmental) budgets.
Budget as a Constraint
To express the idea of a maximum budget for an initiative, we should specialize from the Archimate constraint element:

Adding Visual Indicators
I have added an extra icon to the specialized components to clarify their meaning, specifically an indication of a stack of coins. This can easily be achieved with the specialization manager of Archi.
In the case of the project budget, I also included a simplified Gantt chart symbol (which might be excessive, but the second symbol adds valuable context). There is a potential overlap with the symbol for the Plateau element, which uses the same symbol. However, the relative positioning significantly reduces the risk of confusion.
Adding the Type as Text
I believe it helps viewers to include the Archimate archetype in the last line. Even if the symbols do not yet make sense, the ‘subtitle’ will aid in making sense of the view.