Haram mortgage - how sinful?

Slms how much of a sin is a haram mortgage is it unforgivable. Please can you confirm if possible please can you relate some authenticated Hadith to this question.

Wasalam

May Allah bless you.
Allah says in the Quran: "Say, “O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah . Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.”
So if someone has dealt with interest, then she should repent sincerely, ask Allah for forgiveness and never commit that sin again.
Dealing with interest is haram as mentioned in many places of the Quran and Hadith. There is also a consensus of all scholars on the prohibition of interest.
The prophet (pbuh) cursed the accepter of interest and its payer, and one who records it, and the two witnesses, and he said: “They are all equal.” (narrated by Muslim)
Based on this hadith, we can see that conventional mortgage is also haram because it involves paying the interest.

However, I would like to highlight that some contemporary scholars made some exceptions. The exceptions made is not a general ruling, and does not mean these scholars made interest halal. On the contrary, it means that in some situation, taking a conventional mortgage might be tolerated. This is similar to a situation where consuming pork might be tolerated if it is to save one’s life.

And Allah knows best!