While there are congregations of semi-organized religions, typically only the player characters may perform miracles of Divine Magic.
In the distant past, in the troubled time where the Planes were just beginning to crack at the seams, the Gods suddenly vanished. A great silence befell those who heard the Gods so easily, and any cries for help or desperate prayers directed towards them seemingly went unanswered. Divine magic faltered, religions fell apart, but there were no signs of the Gods anymore. None interfered in the events that had been put into motion, and the planes shattered into the Shards we see today.
In recent times, some beings carrying enough power to call themselves Gods have emerged.
While many will refer to the various sects and cults of various Gods as clergy, and speak of their selected places of worship as temples or shrines, it is more out of habit than those words being true to the reality. Religions are as fragmented as the planes, with no overarching power structures within the faithful that have emerged post Sundering. The vast majority of people do not offer active worship to any God, seeing them as useless after everything fell apart. Some might offer casual worship, a prayer here and there, but little else.
Those who do worship Gods actively are in the minority. Most think of them as- by the strictest definition of the word -cults, as in devoted groups of individuals with peculiar and unorthodox practices. The word carries a more negative connotation, however, so it's rarely used in the presence of the religious individuals in question. They're usually harmless, oftentimes helpful or friendly depending on their practices, so they have been allowed to create their own community spaces in certain populated areas. It's hard to be mad at people seeking comfort after many years of drastic changes, after all.
Clergy or less active worshippers will typically be in smaller groups that practice on their own, leading to a variety of similar, yet never identical methods of worship all done in the name of the same deity. Teachings and prayers can be interpreted in many ways, so it was inevitable that a variety have emerged within these fledgling cults. This is both a point of contention and something of interest between the various sects, and depending on the God, might lead to conflict or collaboration.
Most who do practice a religion and curate a public shrine do so more as a “side gig.” Religion doesn't pay (unless you follow Mask, and are “taking tithes” from pockets) and very few people are interested in donating money to upkeep those spaces. This is part of the reason why these spaces are smaller or rather shabby looking the majority of the time. Clergy, thus, are usually known for whatever other work they do in the community first, and as clergy second. It isn't uncommon, though, for the profession of the clergy to have some ties to their deity of choice. Artisans and engineers make up the majority of Isva's clergy, while surgeons and necromancers may look to Valdis for guidance.