Does the word דרכי [darchei] ever take a dage"sh in the cha'f? As far as I know, it's always rafe"h in every occurance in Tanach, and hence for example the Darchei Mosheh by the Ram"a [as opposed to the Darkei Mosheh]. Would the proper punctuation of a sefer be Darkei Teshuvah [with a dage'sh] or Darchei Teshuvah [without a dage'sh]? What is more proper grammatically? I checked my Even Shushan concordance and he lists 13 occurrences of darchei [and other examples with other suffixes or prefixes] but no examples of darkei.
Where is my mistake in assuming that the sefer would be called the Darchei Teshuvah and not Darkei Teshuvah if darkei is not a word that occurs in Tanach even though darchei is a word that occurs in Tanach*?
Please educate me.
*Other than my general ignorance.
