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LiveView uses Contrast AF which is considerably slower and older technology. However, through your lens, you're using Phase AF.

Here's a really good article on FStoppers about it: https://fstoppers.com/education/difference-between-dslrs-viewfinder-autofocus-and-live-view-autofocus-195881

Phase Detection:

Phase detection autofocus functions using a pair of micro lenses to compare light flowing through opposite sides of the lenses. It then aligns those two images on top of each other. Due to the images being drawn from a different position on the main lens the pair of images will be slightly different. However, the point of critical focus will be perfectly aligned. If this point of critical focus is within the bounds of the active autofocus point, the camera is in a focused state.

Contrast:

Contrast detection autofocus, while comparably complex in theory, is actually much easier to understand in layman terms. When autofocusing in live view, a DSLR records images from the sensor in real time that it then analyzes for the intensity of contrast between adjacent pixels within the bounds of the focus point. If the contrast intensity reaches a required threshold, the camera is in a focused state. Because contrast detection analyzes an image from the sensor itself, the analysis can be done on any area of the sensor without difficulty. For this reason, live view autofocus can target even the far corners of the frame.