Meaning of 的 and 之 when both are used in the same sentence
之 is the classical Chinese counterpart of 的 in modern Chinese

In classical Chinese, writers rarely use compound words if single character words with the same meaning is available. 


  的(昏沉)
  
  之(感)
  
  之(事)
  
  的(說明)


Notice 的 apply to two characters compound words and 之 apply to single character words.

If you switch  the single character words 感 and 事 into compound words 感覺 and 事情, you should also change the classical 之 to the contemporary 的


  的(感覺)
  
  的(事情)


Using 之 with compound words like "之感覺" or "之事情" is not considered grammatically wrong, just sound awkward. It is all about style

Changing '之事' to '的事' is fine, because '事' can replace '事情' in modern Chinese. e.g. "今天的(事情)" can be reduced to "今天的(事)"

However, changing '之感' to '的感' is considered a grammar mistake because we don't use '感' to replace '感覺' in modern Chinese. e.g. "痛苦的(感覺)" cannot be changed to "痛苦的(感)"


  「對於混沌而迷離(1. 的昏沉)(2. 之感)(3. 之事)後(4. 的說明)」


#1 and 4 are common modern Chinese; #2 and 3 are classical style Chinese. 

Yes, we do routinely mix classical style into modern Chinese in our writing and daily conversation. It is all about style, four 的 in a row "...的昏沉的感覺的事情後的說明" make the sentence sounds confusing  -  a bad run on sentence

"...的昏沉之感之事後的說明"  is also a run on sentence
, but at least it is not that bad with different styles mixing in.

Even "...的昏沉之感覺之事情後的說明" is better than "...的昏沉的感覺的事情後的說明"