4 games is really no option I think, too much variance.
The problem is that we need a tie-breaker in a short league like this and I don't see a better option than using match points. If no-one has a better option for tie-breaking, I guess every match should go over the full series of 6 games.
6 games isn't a whole lot so that shouldn't be a problem 
Speaking about variance, if you really want to reduce it as much as possible and want to make the matches more like team efforts where each individual game matters, you could just let the overall score be what determines the outcome. E.g. if the 4 match-ups constituting Belgium - Germany end 2.5-3.5, 2.5-3.5, 2.5-3.5 and 6 - 0, Belgium has won with 13.5 - 10.5.
I think that rather focusses more on individual play rather than team play as the star player (in this example) won for the whole team.
That's one way to look at it, another would be that Belgium was only able to win because the three other players were able to keep their games close, and ultimately their combined efforts of 7.5 points ended up contributing more to the win than the star player's 6 points. There's also the possibility of the "star player"'s opponent just having messed up. This is precisely the point: with this system each individual performance contributes more to the end result because there's a larger reward for a great performance and a larger cost associated with a poor performance, and thus also a decent reward for preventing a poor performance by "only" losing 4-2 instead of 6-0. And isn't that what you're looking for in a team sport? To make your individual actions matter to the group? To be able to compensate for a team mate's bad luck, or to have someone else make up for your poor showing?
The main idea behind my proposal, though, is just to reduce variance: by distributing it across matches, decent chunks are expected to cancel out between them, so by using the total score, luck has a much smaller impact on which country wins the match.
Edit: Also, it disadvantages teams that already have troubles to get a full 4 member team. If the 4th player (that only joined to get a full team) loses 0-6 every time, this team will have big troubles to get a good end result.
Yes, the consequence of reducing variance is that weaker teams have a lower chance of winning, but I contend that that's a good thing. A country with 4 strong players
should crush a country with 3 strong players and a total drooler, you don't want such a match-up to be close due to unnecessary systemic variance.
