How to keep seasonings from separating in soup
You could use a bouquet garni.


https://www.wikihow.com/Make-Bouquet-Garni

https://en.wikipedia.org/wiki/Bouquet_garni


  The bouquet garni... is a bundle of herbs usually tied together with
  string and mainly used to prepare soup, stock, casseroles and various
  stews.The bouquet is cooked with the other ingredients, but is removed
  prior to consumption...
  
  There is no generic recipe for bouquet garni, but most French recipes
  include thyme, bay leaf and parsley.[2] Depending on the recipe, the
  bouquet garni may also include basil, burnet, chervil, rosemary,
  peppercorns,[5] savory and tarragon.. Sometimes, the bouquet is not
  bound with string, and its ingredients are filled into a small sachet,
  a piece of celery stalk,[3] a net, or even a tea strainer, instead.


I have usually done this with cheesecloth.  If your herbs are dried as in this picture that would be how you do it too.  Make a bag of cheesecloth, fill it with herbs and tie it with string.  Remove from the finished soup and throw it away, so you do not eat it by accident.