Lucky metals or gems will not work unless you are using fashion to impress or attract a partner
Worship to a Daiva or Puja to a certain Daiva will indoctrinate alot of that Daiva's energy within you as they are also a manifest of the Paramātma but represent different aspects of nature.
For women, worship to Shivashankara on Monday's are done because of Shivashankara's unchangeable love toward Ma Parvati as well as getting a husband who helps them improve their wisdom in life as Shivashankara and Ma Parvati had alot of discourses about life, living and sciences both material and spiritual
Warriors also worshipped him because he represents destruction and the relief from worst possible sufferings and deaths so they sought moksha from him if they had the most gruesome death at the hands of an enemy
Married couples and householders also do Suryanarayana katha for preservation and family lineage health reasons. Also worship is done to Narayana because in all of his Avatara, he tried his absolute best to take care of his partner even if "karma" seemed to go against the situation like in case of Shrī Rama and Ma Sīta or Shrī Krishna and Ma Radharani.
So when worship is done to them for something, it is an aspect of nature that you wish to embibe within your personality which in luck and divine blessings would make certain desires be fulfilled through this or there can be direct divine intervention depending
So if a person worships Shivashankara and Ma Parvati or Lakshmīnarayana for marriage, the person will take on characteristics of those Daiva or receive their blessings so they can use it to make obtaining marriage easier.
In a more comical example, as a remedy for fixing a marriage and to have a child I told the person to do a Mantra of Kamadaiva. After several months, a consistently long time he did not feel anything develop but all of a sudden he started to get learning material in extense about his case in which he learnt. The marriage was fixed and he mentioned that his wife was pregnant with their child soon after
But its not always a guaranteed case. I tried repeating the similar remedy to someone else. They also found ways to learn about those matters but it didnt help in marriage and to no surprise, Shukra was under extreme grip of prarabdha karma graha implying kriyamana karma cannot be used and person has to wait for one particular person to enter their life in order for the event to happen.
This is how the whole remedy cycle works. It may not solve karma completely but certainly helps you somehow