There have been occasions where a player has gone afk for the entire game and a 5/5 surrender requirement would mean the vote would always fail. I think 4/5 would be better, or maybe 1 less than the number in a team to take into account any disconnects (so 4/5, 3/4, 2/3 etc).
There are other aspects to surrendering that need sorting/fixing. Sometimes the surrender vote never appears - I’ve had 2 or 3 games where we’ve lost by surrendering and I never saw the call to surrender option (as on those occasions I’d have voted against as we weren’t losing that badly).
The devs also need to fix surrender votes so they can’t be called when a team is only a few points away from a win and to prevent surrender votes being called when there’s only a few points difference between the team scores.