I'm not sure what you mean by "your total would be far lower than here". Do you mean COVID cases? In NS, it's essentially zero right now. Every couple of weeks, or so, a case will pop up where a traveler coming in from outside the bubble will test positive. But, because such people have been following the 2-week isolation rules, they haven't caused any spread. I believe there may be one unresolved case right now, in hospital.
Population density doesn't tell us a whole lot about how closely grouped people are. It's the concentration of people that counts. For example, almost half the population of NS lives in the Halifax area. Newfoundland and Labrador has a population density of just 1.4 people per square kilometer - but, 92% of the population live on the smaller island portion and over half them live on the Avalon Peninsula surrounding the capital, St. John's.
And, public interactions and opportunities for COVID spread are probably not a whole lot different, no matter where you go. People in larger populations probably don't shop, take transit, have parties, etc than people in smaller populations. I'm sure population density has some influence, but it certainly isn't directly proportional. There are many variables that influence virus spread.
The biggest differences in the degree of success in containing the spread are the protocols in place to reduce the risk of spread and the population's willingness to follow them.