A high-end curved ultrawide monitor is a major desk upgrade that should last you at least five years. Don't rush into a purchase that you will need to replace because of poor build quality or outdated tech.
Tech brands usually refresh their lineups in early spring. Wait for holiday sales to target last year's flagship models, which often drop significantly in price while remaining top-tier performers.
That 18-month window is a deadline, not free money. If you have a balance remaining after the 18 months are up, the card will start charging you regular interest, which gets expensive quickly.