The phrase "grandiose plans" means having big, ambitious, or extravagant ideas or goals. It refers to someone's desire to achieve something on a large or impressive scale. Full definition
In the process, some of Apple's more grandiose plans for iOS 12 — such as a revamped homescreen — will reportedly be put on the shelf until iOS 13 in 2019. (bgr.com)
If it came to, say, $ 100, I wouldn't make grandiose plans about buying a new Mercedes. (money.stackexchange.com)
In 1517, an unknown German professor from an undistinguished new university protested against the sordid trade in religious benefits known as «indulgences,» which were then being peddled around Germany to fund grandiose plans to rebuild St. Peter's Basilica in Rome. (firstthings.com)