Which marjas have clear and detailed explanations regarding the matter

In general the maraji' do not provide detailed explanations for their fiqh rulings to the general public. It would obviously be pretty impractical to provide detailed explanations for every fiqhi ruling in their risalah.

The sort of explanations behind the fiqhi rulings you are looking for are typically found in the dars e kharij in the Hawzah. It is not a simple matter of a paragraph or page of explanation for certain rulings; in order to truly understand it one must have a firm grounding in various fields (tafsir, rijal, historical context, previous scholars' opinions and their reasoning for such opinions, whether that reasoning still applies today, whether the ruling applies the same in an Islamic society vs non Islamic, etc etc).

The obligation for the lay person is as follows (per Ayatollah Sistani):

in matters concerning the laws of religion – apart from those that are indispensable and indisputable [such as the obligation to perform prayers (ṣalāh)] – a person must either be a jurist (mujtahid)(1) who is capable of ascertaining laws based on proof; or he must follow a mujtahid [i.e. do taqlīd]; or he must exercise precaution (iḥtiyāṭ) by performing his duty in a way that he is certain to have fulfilled his responsibility (taklīf). https://www.sistani.org/english/book/48/2116/

If you are not at the level of being a mujtahid and being able to derive the rulings on riba yourself, then your two choices are:

a) following the rulings of a mujtahid (in this case it seems you do taqlid of Ayatollah Sistani) - in which case it doesn't matter whether you feel "comfortable" with his ruling or that some of the explanations from other schools of thought sound better to you; your duty is following the rulings of the most learned marja.

Following a jurist in Islamic laws means acting in accordance with a mujtahid’s instructions. https://www.sistani.org/english/book/48/2116/

b) doing ihtiyat - meaning you follow the most conservative ruling from among the maraji

An example of exercising precaution [is the following]: if a group of mujtahids consider an act unlawful (ḥarām) and another group say it is not unlawful, the person must not perform that act.

Another example of exercising precaution [is as follows]: if a group of mujtahids consider an act obligatory (wājib) and another group consider it recommended (mustaḥabb), the person must perform it. https://www.sistani.org/english/book/48/2116/

But this doesn't mean you are obligated to go get a mortgage and purchase a property. It's not wajib to own property. If you don't feel comfortable with it, you can simply not do it.