Viewing predictions on when you reach certain milestones is easy. With the /<game> project [statistic] [value] command, you can view when a player will reach any milestone, for any statistic, for any mode, in any game.
By default, StatPixel will choose an applicable milestone to project to. If you want to specify a milestone, you can do so by adding the [value] argument to the command. For example /bedwars project statistic:Wins value:1000 will calculate the time it will take for a player to reach 1,000 wins in Bed Wars.
The [statistic] argument is used to specify which statistic you want to project. For example, /bedwars project statistic:Level will project their level, and /woolwars project statistic:Wool Placed will project the amount of wool they place in Wool Wars.