A high-quality ultrawide monitor is a major productivity boost that should last you five years or more. Buying a top-tier display once is smarter than settling for something smaller that you will want to replace in a year.
Tech manufacturers typically refresh their flagship monitors in early spring. Wait for the back-to-school sales in late summer or the heavy discounts in late autumn to pick up last year's model for a fraction of the original price.
That 0% window is a deadline, not a gift. If you still have a balance left when the 18 months are up, the bank will charge you standard interest on whatever is remaining.