Dr. Devereaux of A Collection of Unmitigated Pedantry has a really nice overview of the position of Roman dictator over at his blog. [1]
The very short version is that 'dictator' refers to two different things. One version is the dictator appointed by the Senate in the early Republic to solve a particular crisis, who had absolute power within their sphere of responsibility and who uniformly relinquished power when their job was done.
The later dictators towards the end of the Republic were Sulla and Caesar. They seized Rome by force, then claimed the long-disused title of 'dictator' to give their actions an appearance of legitimacy.
The very short version is that 'dictator' refers to two different things. One version is the dictator appointed by the Senate in the early Republic to solve a particular crisis, who had absolute power within their sphere of responsibility and who uniformly relinquished power when their job was done.
The later dictators towards the end of the Republic were Sulla and Caesar. They seized Rome by force, then claimed the long-disused title of 'dictator' to give their actions an appearance of legitimacy.
1. https://acoup.blog/2022/03/18/collections-the-roman-dictator...