I'd be interested in your response to a question. In 1 Cor 15, Paul mentions that Jesus appeared to more than 500 of the brothers, yet in Acts 1:15, the number of believers was only about 120. I've been trying to reconcile this and was wandering if after the resurrection there may have been a systematic persecution of believers, hence by the time of Jesus' ascension, perhaps some had died as a result, hence the mention that some had fallen asleep. What are your thoughts?

1 Cor 15 refers to the Galilee appearance. The 120 are in Jerusalem.

There's no need to suppose persecution reduced the 500 figure. In Jerusalem the Christians were waiting, as instructed, before the Spirit came upon them (see Luke 24).

So it’s not necessary to reconstruct any elaborate theory to account for the different numbers!