u/AdObjective9410

I saw a video of shaykh salih luhaydan رحمه الله where a question was asked that someone missed salah for 18 days the repented.

He mentioned that its serious fault, but then mentioned that the person's previous good deeds before that have now become like dust and all nulified i know that there is a strong opinion that leaving salah is kufr but my question is: if I ​miss one salah without an excuse or 2 or 3 and then repent and pray rest of my Salah are all my good deeds previous to that point now Nulified?