Just to make sure, do you pronounce plus with or without the ending /s/ in the phrase "plus de l'avant"?
My understanding is that "plus + NOUN" leads to the ending /s/ sound being pronounced, but "plus + ADVERB" results in no ending /s/ sound.
The word "avant" can be an adverb and a noun.
However, the indefinite article "de l'" suggests that "avant" is a noun, so I am guessing that "plus" is pronounced with the ending /s/ here.
Please let me know if this is correct or if I am mistaken.
I would say - pronounce the s - it sounds better that way