Zimbabwe's bowlers have undoubtedly performed well. I would say that Zimbabwe won because of the controlled bowling of their bowlers. If the bowlers had not done well, Afghanistan would have given a target of at least 180+ in today's match. Zimbabwe would not have been able to win by batting against a big target against Afghanistan.
Zimbabwe won the first match. However, I think Afghanistan will win this series. Zimbabwe also won the first match of the series against Pakistan. However, Zimbabwe lost continuously after that. Afghanistan will probably win the next two matches against Zimbabwe.
You are right, bowlers contributed more to Zimbabwe's win yesterday. The Zimbabwean bowlers bowled brilliantly early on, dismissing two of Afghanistan's opening batsmen early on which put Afghanistan under pressure. In the end, Afghanistan managed to score 144 runs. A target of 145 runs is not a big enough target in the T20 format. In the end Zimbabwe surprised everyone and won by four wickets.
Afghanistan's bowlers also tried their best, bowling brilliantly to take the game to the last ball. But ultimately failed as the target was low. Afghanistan still has a chance. If Afghanistan can perform well in the next two matches, they will win the series. I also think Afghanistan lost the first match, but will turn around in the next 2 matches and win the series.