I prefer to think that they are struggling to score goals rather than not trying to score many goals in a match because looking at their condition for the beginning of this season it seems very difficult for them to score more than 2 goals in 1 match.
There still needs to be some familiarisation when trying out some of the younger players and Lewandowski's performance is still hampered by the opposition's marking which makes it difficult for Barcelona to find many goals in their matches.
Despite this the chances of them winning definitely remain as they are the favourites and the worst possibility is a draw although this would be difficult for Betis to force a draw.
I just hope Robert Lewandowski get back to his full potential like that at Bayern Munich were he could be able to score several hat tricks in one season, ever since he came to Barcelona I've not really been impressed with his performance compared to when he was at Bayern Munich, Barcelona are known to be very dominant and very high in possession on the pitch, they love to press their opponents and force them out of their defense line which is a very fine tactics that could make them easily win matches against smaller club but you'll find them pressing and failing to put the ball into the net, and it would fall back to Lewandowski inconsistency for Barcelona, since he's the top 9 it's his responsibility to get the ball into the net but it's been uneasy for him instead it's the Barcelona wingers and Midfielders that mostly scores for them.
It's difficult, Lewandowski is a good player but on the other hand, we also have to remember that his age has started to interfere with his performance so it's impossible to expect the same performance when at Bayern which was Lewandowski's golden era.
But he will still be very useful for now for Barcelona, it's just that until now it seems that Lewandowski is still very difficult to get his form at the beginning of this season.
It's up to Xavi to revive Lewandowski and it's up to Lewandowski whether or not he can break free from his current state because from what some of Barcelona's opponents have done at the start of this season they know that keeping Lewandowski at bay is a top priority and letting Barcelona have more of the ball.