Grandeur does have negative connotations but there's plenty to unpack. When something is grand or grandiose, it has the potential to draw attention, to amaze, and to leave people in awe. For many, it can also be inspiring and motivating, showing them that great things can be accomplished and that it is fantastic when they are. It may even call them to stop focusing so much on trivial matters and instead work toward something bigger than themselves. For others, however, it is no more than offensive, for which they get defensive about. But they are not necessarily entirely wrong.
Art enables the pursuit of grandeur. There is so much that you can do in a work of art. Seeking and gathering the best materials, employing the best tools, putting in a baffling amount of time and effort into it, perhaps even uniting the most talented and skilled artists. All so that it will inevitably stand out. Maybe break one or more records, too. Make people speechless. And in many ways, indulging this craving pushes you to fulfill your potential. So it is not merely a vain attempt for external validation, applause, and adoration, but a purpose to test yourself and what you're capable of, gaining mastery and expertise in the process.
Besides, what is the worst that can happen when you aim for it? That you fail to meet your standards and expectations and become disappointed in yourself? That you are laughed at and told "I told you so" for not succeeding? That, in the end, it was a waste that left you with little to show? You will have to decide if it is still worth it to you or not. What would be a worse regret?
Some people are born with an innate desire to do the "impossible", to break the limits and go beyond, to take all that they are gifted with and make the most of it, or simply to be as astonishing as they can while they still can. If you are one of them, quieting and denying that desire can be severely detrimental to you. It can make you apathetic, listless, and stagnant.
Yes, there are other things in life that are also important - arguably more important. But to some, this is everything. Yet, it can be a particularly difficult path because of the resistance that they face. Their aspirations viewed as insane or selfish (and secretly or not so secretly, as threatening). It isn't until it has yielded major benefits and that those benefits are shared that opinions begin to change or at least lose volume (and rivals might accept defeat or cease to undermine them).
Nevertheless, practicing good judgment is still rewarding. You don't have to be completely self-centered or single-minded to pull off something grand. You don't have to lose friends and gain enemies out of callousness and carelessness if it can be helped. There is only so much that you can balance and tend to at once, but you can keep from falling into the pitfalls of causing more damage than is necessary.
It is tempting to see everything other than what you're fixated on as worthless and dismiss it as such, becoming excessively arrogant, but remember that you give others permission to dismiss what matters to you when you dismiss what matters to them for no good reason. And it is cruel if not just rude.
You don't have to play small for others' convenience and comfort, but you can strive to be and do your best all through it.