Brazilian authorities run open testing from time to time and fixes (tangencial so far) vulnerabilities. So far, there were zero proof that any hacking or flaw in our voting system. This only became an “issue” because discredit the election became part of Bolsonaro’s coup attempt. (Which is, btw, the authoritarian wannabe playbook.)
Anyway, you should witness the mess it was before, when votes were in paper and counting by hand. Frauds was widespread. I mean, look and the US election system… it’s a kind of meme in Brazil due to how rudimentary and prone to fraud.