The decision-maker is the elected governing body for the common property, not an individual resident and not, on its own, the manager. Connecticut's Common Interest Ownership Act calls it the executive board. Massachusetts chapter 183A works through the organization of unit owners, which may be self-managed by elected trustees or a managing board and may appoint a manager or managing agent. New York condominium bylaws must provide for a board of managers and set out its powers.
The manager's role is operational and it matters, but it has a boundary. Community Associations Institute guidance describes a manager preparing and screening proposals while stating that the final authority to hire or terminate a vendor stays with the board. The practical shape, unless your documents say otherwise: the manager recommends and administers, the board authorizes.
One more thing worth knowing before a proposal reaches a meeting. CAI reminds boards that directors are fiduciaries and that vendor hiring is where accusations of self-dealing surface, so the selection should be fair, any conflict disclosed and recorded in the minutes, and a conflicted director should sit out the vote. We mention it because it shapes how a proposal should arrive: comparable, documented and unhurried, rather than as a favor to somebody's cousin.