How can scroll could be smoother (when clicking a link that redirects the user to another section on the same page)?

The scroll-behavior CSS property sets the behavior for a scrolling box when scrolling is triggered by the navigation or CSSOM scrolling APIs.

/* Keyword values */
scroll-behavior: auto;
scroll-behavior: smooth;

/* Global values */
scroll-behavior: inherit;
scroll-behavior: initial;
scroll-behavior: unset;

Note that any other scrolls, such as those performed by the user, are not affected by this property. When this property is specified on the root element, it applies to the viewport instead. This property specified on the body element will not propagate to the viewport.

Source: https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-behavior