Depending on what you like to eat, and if you can only have one, a Blackstone griddle may be a good choice. You can cook hash browns, eggs, pancakes, sausage and bacon. And you can cook burgers, chicken, fish.
For me, I've got a Blackstone griddle for those things that are best suited to it. And I've got a Weber Q grill for cooking steaks, burgers, pork chops, chicken, kabobs and such. Next to the Weber is a smoker for ribs, brisket, smoked salmon, tri tip, Thanksgiving turkey, pork shoulder, occasionally smoke a steak before grilling it.
So for me, if I could only have one, it would be a pellet smoker that is rated good at also doing direct heat. Then get a griddle that fits on it. Then you can do it all. But if your not into smoked meats, then the Blackstone griddle would suit you fine.