Abbeys anyd Temples

Small typo.

I find that both of themFrom what I’ve seen, both faiths are prone to building in remote areas, such as on mountain tops, rugged coasts, and isolated islands.

1) Rephrasing ‘ I find that’ in a manner similar to what I’ve written in the revision adds more clarity.
2) Rephrasing ‘both of them’ as ‘both faiths’ clarifies its meaning.

Aside from that, the mechanics of this sentence are solid.

It's also not surprise that we can see some of them built within citiesHowever, some were built within cities as well; disciples from both religions need tranquil settings for meditation, after all.

Combining this sentence with the next sentence via a semicolon expresses the ideas found in both in a more efficient, connected manner.

Both the two disciples from these religions need tranquil settings for meditation.

Abbeys anyd Temples

Abbeys are places for Christian Monks and Nuns to live, while temples are for Buddhists to dwell.

Everyday people do not live in abbeys or temples, so you should say what kind of people live there.

I find that both of them prone to be buildt in remote areas, such as on mountaintops, rugged coasts, and isolated islands.

or "I find that both of them are often built in"

It's also not surpriseing that we can see some of them built within cities.

Both the two dDisciples from both of these two religions need tranquil settings for meditation.

Abbeys anyd Temples

I find that both of them prone toare buildt in remote areas, such as on mountaintops, rugged coasts, and isolated islands.

It's also not a surprise that we can see some of them built within cities.

Both the two disciples from these religions need tranquil settings for meditation.

I find that both of them are prone to being buildt in remote areas, such as on mountaintops, rugged coasts, and isolated islands.

The abbeys and temples are the things which are being built (the grammatical objects), so you should use passive structure like this

It's also not a surprise that we can see some of them built within cities.

"It's also not surprising" would be correct as well

Both the twoThe disciples from both of these religions need tranquil settings for meditation.

Abbeys are places for Christians to live, while temples are for Buddhists to dwell.

This is grammatically correct but factually inaccurate: many temples are non-residential (no monks live in them) and are associated with other religions besides Buddhism.

I find that both of them [are prone to being | tend to be] buildt in remote areas, such as (on) mountaintops, rugged coasts, and isolated islands.

It's also not surpriseing that we can see some of them built within cities.

Both the two dDisciples [from these| of] [both of these | these two] religions need tranquil settings for meditation.

Your original wording describes two people (disciples), one from each religion.