The fact that all large modern institutions are thoroughly corrupted by political correctness and secularism (including all major churches) implies that pursuit of The Good is now restricted only to individuals (or small - probably informal - groups) - which in turn leads to a consideration of how individuals can - potentially - 'make a difference'.
1. There is a 'fake' way in which individuals can be argued to make a difference, and that when an individual is arbitrarily taken-up by a large and powerful interest group and used as a propaganda weapon.
This applies especially to designated victims (real, or contrived - it does not matter much) - of whom Rosa Parks is perhaps the best known example in the USA; although there have been many others throughout the West.
Clearly an individual becoming a tool of establishment power is not really what is meant by an individual 'making a difference'.
2. Individuals who truly make a difference do so by their example, which changes the lives of many other individuals.
Examples might include the Holy hermits of 'the desert' such as St Anthony of Egypt, St Cuthbert of Lindisfarne or St Seraphim of Sarov - people who sought and attained ascetic isolation for many years during which they developed their spirituality to an extremely high level, before returning to the world to teach and inspire.
While of course these figures can be (and are) later used for propaganda purposes (with all the selection and distortion this entails) - they are primarily examples, and individuals who were originally sought-out (rather than promoted) by people recognizing their special intrinsic qualities and responding to word-of-mouth outside of 'official channels'.
Other examples can be found in less perfectly-achieved forms, and also among types of non-religious 'creative genius' - albeit many/ most creative geniuses in the arts and sciences were bad examples in many/ most ways other-than their specific creative gifts.
So, yes indeed, individuals can 'make a difference' - and the real examples of individuals making a difference are usually quite easy to distinguish from the fake - at least in the early stages of their making a difference.
Of course, there are also individuals who make a difference-for-the-worse - and there are plenty of these, and some have made a truly enormous difference for the worse: quantitatively far-outstripping and of the measurable effects of Saints, and operating with extraordinary rapidity.
But while building is slow and incremental, destruction is swift and facile - evil geniuses are pushing at an open door.
One sure way to discern the difference between real/ good and fake/ evil individuals-of-influence, is that the real and good individuals who make a difference only do so after many years of disciplined struggle. This is necessary - albeit not sufficient.
As a rule; any individual who makes a large and rapid difference without prior years of struggle is either a fake tool-of-propaganda or else 'demonically-inspired'.