ANSWER:
It is our duty to give dawah but the results are in Allah’s hands.
The prophet salla Allahu alaihi wa sallam had told us that on the day of judgment, there will be a prophet with great followings, a prophet with little following and a prophet with one or two men following him and a prophet with not a single follower.
Therefore, keep up the good work and anticipate the reward from Allah and don’t pay attention to the number of people who accept your dawah as it doesn’t matter.