This feat is granted for free if you meet the requirements: Druid 2024 edition, Wild Shape class feature.

When using Wild Shape, you do not gain temporary hit points equal to druid level, nor do you keep your own Hit Points and Hit Point Dice. Instead, use the following rule from Druid 2014 edition:

When you transform, you assume the beast's hit points and Hit Dice. When you revert to your normal form, you return to the number of hit points you had before you transformed. However, if you revert as a result of dropping to 0 hit points, any excess damage carries over to your normal form. For example, if you take 10 damage in animal form and have only 1 hit point left, you revert and take 9 damage. As long as the excess damage doesn't reduce your normal form to 0 hit points, you aren't knocked unconscious.