Random variation or chance is a non-being. Self-creation is a violation of the law of noncontradiction. Random variation does not 'cause' anything other that than random variation combined with selective forces can be used as a causal explanation of observed facts. Your assumption that random variation should be able to influence a system or that chance needs to be a 'being' or that it needs 'instrumental' power are all very subjective words. For instance gravity causes a ball to drop when released.
Solar energy causes water to evaporate and causes rain when the water precipitates.
I believe our disgreements appear to be caused by definitions of words.