Assalamu alaikum wa rehmatullahi wa barakatuh
Counting all the specific and non specific words Day would give you the number of 365,i.e. the number of days when you follow a Calendar based upon the movement of Earth around the sun.
Counting only the simplest words Day would give you the total of 354,the number of days in an Islamic Calendar.
For both cases,the dual forms and the words with pronouns are not counted.
The words yawm:
The verses where the words yawman or bada yawm are used,from there only the single word Yawm is considered.
It is really the simplest set giving you the total of 354.
The words Yawm with a single letter as Prefixed Preposition:
The words Yawma-idhin i.e. That day:
274 + 12 + 68 = 354