iCloud storage does NOT “magically”, increase the FIXED internal data storage inside of your iPad.
What iOS/iPadOS version is this iPad, currently, running?
What is the rated, internal data storage space/capacity of your iPad model and how much of this free, internal data storage capacity is left inside of your iPad model?
All of that additional info can be found in the Settings app, General settings panel, About.
I suspect you own a low data storage iPad model and that internal data storage is nearly used up!
FYI,
iOS devices and iOS/iPadOS need to maintain, at the very least, a minimum of between 3-6 GBs of free data storage space, AT ALL TIMES, to insure normal/nominal functionalities/operation and general overall performance of any iOS device running iOS/iPadOS.
Please attempt to answer all questions asked.
Thank You.