Lightroom Classic CC: Distortion correction too weak

Why not try applying like 75 and then apply what is needed to fulfill what your mind desires. In other words, try doing a twice - one after another.
RONC

What lens and camera model  and are you using raw files with Lens profile Distortion correction or JPEG files with Manual Distortion control? I tested my Canon 8-15mm fisheye lens on both full-frame and crop sensor cameras and Lens Profile Distortion set to 100 provides near perfect rectilinear correction at 8 mm focal length with raw files. The Manual Distortion control is not designed for correcting fisheye lens distortion.