Accessible line height for headings (h1, h2, h3, etc)

We are working on making our product's typography WCAG accessible.

This is what MDN says regarding the line-height:

Use a minimum value of 1.5 for line-height for main paragraph content. This will help people experiencing low vision conditions, as well as people with cognitive concerns such as Dyslexia. If the page is zoomed to increase the text size, using a unitless value ensures that the line height will scale proportionately.

Technically they mention only main paragraph content "p" tag.

Our question is:

What line-height value should we use for headings and buttons? Should we use at least "line-height: 1.5" for headings, buttons, and other text elements as well, or just for "p" tags?

Is line-height value smaller than 1.5 accessible for H1 and other headings?