If you have both been living out on your own, or defacto, you will likely already have several irons, toasters and kettles, and enough manchester and napery to open your own department store. You may feel that if you have an engagement party you will get lots of unnecessary items.
You can have a party and specify NO GIFTS, or even have no party but beloved relatives will still sneak you gifts.
I’ve been to engagement parties on a chicken farm, and a horse stud, both of which were really well organised events. The invitations said "no gifts, but ladies please bring two dishes (salad, pasta, dessert) and men please bring firewood / contribute to the beer keg fund". At the chicken farm, the family provided fresh chicken cooked in many different ways, at the horse stud, the family had a lamb, goat and pig on a spit (hence the request for firewood!). In each case, 40-60 people ate themselves silly and had rousing great celebrations. Seating at the horse stud party was hay bales and planks on bricks. Drunken guests bought sleeping bags and slept in the back of their vehicles. These ideas would still work well in the city, in a backyard, providing the yard is large enough and there is enough room for parking!