1400sqf = 130m2

Typically in Australia we’d size for 180W/m2 which in a domestic setting gives plenty of heads room.

130x180 = 23.4kW unit. This size it would be a ducted unit to ensure proper distribution of cooling throughout.

2.5tonne equates to approximately 8.8kW which only gives you 68W/m2 which as an ex mechanical engineer is completely undersized at least for Australian summer.

Without knowing more the only suggestion I would give is set the target temperature a bit higher. This increases the units efficiency and should help it get to temperature quicker.

If you’re uncomfortable try running an additional fan. The movement of the air will make you feel cooler even if the air temperature is the same.