Have the t=caps in spotweb return:
...
<search available="yes" supportedParams="q"/>
<tv-search available="yes" supportedParams="q,season,ep"/>
<movie-search available="yes" supportedParams="q"/>
...
That will let Sonarr know that you don’t support rid= and would like to get q= queries.
Please note that in the latest nn+ standard the supportedParams attribute is supplied as well, so apps can determine what the indexer supports.