Profile card component

That looks great. I particularly like the polished readme file too, makes a great first impression.

For the solution itself, I think there are too many heading elements. The user's name makes sense to be the heading for the card, but I think the others don't makes sense as headings. They're not labelling something or defining a new section.

I'd maybe structure it something like:

<main>
  <h1>My Page</h1>
  <article>
    <h2>Victor Crest <span>26</span></h2>
    <p>London</p>
    <ul>
      <li><span>80k</span> <span>Followers</span></li>
      <li><span>803k</span> <span>Likes</span></li>
      <li><span>1.4k</span> <span>Photos</span></li>
    </ul>
  </article>
</main>

That way you can probably avoid adding too many wrapper divs to that as well.

It might be neat to model the bottom section as a definition list, rather than a regular unordered list, but the problem is in the design the term <dt> (Followers) comes below the definition <dd> (80k). And for the html to be valid the dd must come before the dt. You could flip the visual order using flex-order, but then that would violate https://www.w3.org/TR/WCAG20-TECHS/C27.html

I like the animation on the profile photo, that's cool. Make sure you switch it off in a media-query for users with prefers-reduced-motion. You can see an example of how to do that in https://piccalil.li/blog/a-modern-css-reset/

I'm impressed by your commitment to browser fallbacks! I should probably think about that a bit more when there's no tooling to add them automagically...

To me the heading hierarchy seems odd - if the user's age is h2 and location is h3 that suggests to me that location is a subsection of age, which doesn't make sense to me.

Similarly, the card__profile-stat nodes seem backwards; you could make those divs into sections and reverse the order of the h and p for a better result (IMO):

<section class="card__profile-stat">
    <h3>Followers</h3>
    <p>80K</p>
</section>

Re-ordering visually them with flex-direction won't affect their order in the document:

.card__profile-stat {
    display: flex;
    flex-direction: column-reverse;
}

Oh, I'd leave the alt tags on your circles blank too, like you have some other images.