What is the best voting system/electoral system for a small community (10 voters) and 5 candidates where 3 of them become president/admin?

Context: Discord Server Voting System

We're running a political simulation on our Discord server with friends for admin role this is nothing serious just fun. Our community consists of 10 voters, and we have 5 candidates competing for 3 positions (president/admin).

We've tried a couple of voting systems. First, we used a Bracket System with Challonge.com, which involved 1v1 matchups where the winner takes all. However, this didn't work well for selecting 3 winners because it took way too long.We also used a Ranking System where each voter ranks all candidates. but were still not sure how to process this data. We're debating between taking averages or using an algorithm like the one on RCV123.org.

please give your ideas.