To be fair, GP has a point: unexpected expenses and delays in construction represent sunk costs, and don't matter with respect to maximising profits, as the landlord should pick the price which maximises profits with respect to whatever the operating costs of the apartment are, without considering the cost of construction.
However, as sibling comments to yours mentioned, there are flaws to this perspective:
- You can make the apartments 'better' and charge a premium on top of whatever the better appliances cost. So if that raises operating costs by $100/unit month, raise rent by $200/unit month.
- Real life doesn't always map perfectly onto microeconomic theory. In particular, discovering the profit-maximising price is tricky. However, I would still argue that the landlord would rationally still pick whatever they would assume the profit-maximising price would be.
- Since everyone else is probably facing delays and cost overruns, probably not as much construction is getting done as might have been assumed, therefore the landlord faces less competition than anticipated and can raise rent higher than expected without losing too many prospective tenants.